Coating compositions exhibiting corrosion resistance properties and related coated substrates

ABSTRACT

Coating compositions are disclosed that include corrosion resisting particles such that the coating composition can exhibit corrosion resistance properties. Also disclosed are substrates at least partially coated with a coating deposited from such a composition and multi-component composite coatings, wherein at least one coating later is deposited from such a coating composition. Methods and apparatus for making ultrafine solid particles are also disclosed.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with Government support under Contract No.FA8650-05-C-5010 awarded by the United States Air Force. The UnitedStates Government may have certain rights in this invention.

FIELD OF THE INVENTION

The present invention relates to coating compositions that comprisecorrosion resisting particles such that the coating compositions exhibitcorrosion resistance properties. The present invention also relates tosubstrates at least partially coated with a coating deposited from sucha composition and multi-component composite coatings, wherein at leastone coating layer is deposited from such a coating composition. Thepresent invention is also related to methods and apparatus for makingultrafine solid particles.

BACKGROUND OF THE INVENTION

Coating systems that are deposited onto a substrate and cured, such as“color-plus-clear” and “monocoat” coating systems, can be subject todamage from the environment. For example, corrosion of a coated metallicsubstrate can occur as the substrate is exposed to oxygen and waterpresent in the atmosphere. As a result, a “primer” coating layer isoften used to protect the substrate from corrosion. The primer layer isoften applied directly to a bare or pretreated metallic substrate. Insome cases, particularly where the primer layer is to be applied over abare metallic substrate, the primer layer is deposited from acomposition that includes a material, such as an acid, such asphosphoric acid, which enhances the adhesion of the primer layer to thesubstrate. Such primers are sometimes known as “etch primers”.

As indicated, in some cases metallic substrates are “pretreated” beforea primer coating layer is applied (if such a primer coating is used).Such “pretreatments” often involve the application of a phosphateconversion coating, followed by a rinse, prior to the application of aprotective or decorative coating. The pretreatment often acts topassivate the metal substrate and promotes corrosion resistance.

Historically, corrosion resistant “primer” coatings and metalpretreatments have utilized chromium compounds and/or other heavymetals, such as lead, to achieve a desired level of corrosion resistanceand adhesion to subsequently applied coatings. For example, metalpretreatments often utilize phosphate conversion coating compositionsthat contain heavy metals, such as nickel, and post-rinses that containchrome. In addition, the compositions used to produce a corrosionresistant “primer” coating often contain chromium compounds. An exampleof such a primer composition is disclosed in U.S. Pat. No. 4,069,187.The use of chromium and/or other heavy metals, however, results in theproduction of waste streams that pose environmental concerns anddisposal issues.

More recently, efforts have been made to reduce or eliminate the use ofchromium and/or other heavy metals. As a result, coating compositionshave been developed that contain other materials added to inhibitcorrosion. These materials have included, for example, zinc phosphate,iron phosphate, zinc molybdate, and calcium molybdate particles, amongothers, and typically comprise particles having a particle size ofapproximately a micron or larger. The corrosion resistance capability ofsuch compositions, however, has been inferior to their chrome containingcounterparts.

As a result, it would be desirable to provide coating compositions thatare substantially free of chromium and/or other heavy metals, whereinthe compositions can, in at least some cases, exhibit corrosionresistance properties superior to a similar non-chrome containingcomposition. In addition, it would be desirable to provide methods fortreating metal substrates, including bare metal substrates, to improvethe corrosion resistance of such substrates, wherein the method does notinvolve the use of chromium and/or other heavy metals.

SUMMARY OF THE INVENTION

In certain respects, the present invention is directed to primer and/orpretreatment coating compositions, comprising: (a) a thermosettingfilm-forming resin formed from the reaction of a polyamine with an epoxyfunctional polymer; and (b) corrosion resisting particles comprisingmagnesium oxide particles having an average primary particle size of nomore than 100 nanometers.

In some respects, the present invention is directed to aluminumsubstrates at least partially coated with a primer and/or pretreatmentcoating comprising: (a) a thermoset film-forming resin that is thereaction product of a polyamine and an epoxy functional polymer; and (b)magnesium oxide particles having an average primary particle size of nomore than 100 nanometers.

The present invention also relates to methods for enhancing thecorrosion resistance of an aluminum substrate. Such methods comprisecoating at least a portion of a bare metal substrate with a primerand/or pretreatment coating composition that comprises: (a) athermosetting film-forming formed from the reaction of a polyamine withan epoxy functional polymer; and (b) corrosion resisting particlescomprising magnesium oxide particles having an average primary particlesize of no more than 100 nanometers.

In certain respects, the present invention is directed to primer and/orpretreatment coating compositions, comprising: (a) a polyacrylate; (b) apolythiol; and (c) corrosion resisting particles comprising magnesiumoxide particles having an average primary particle size of no more than100 nanometers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart depicted the steps of certain methods for makingultrafine solid particles in accordance with certain embodiments of thepresent invention;

FIG. 2 is a schematic view of an apparatus for producing ultrafine solidparticles in accordance with certain embodiments of the presentinvention; and

FIG. 3 is a detailed perspective view of a plurality of quench streaminjection ports in accordance with certain embodiments of the presentinvention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

For purposes of the following detailed description, it is to beunderstood that the invention may assume various alternative variationsand step sequences, except where expressly specified to the contrary.Moreover, other than in any operating examples, or where otherwiseindicated, all numbers expressing, for example, quantities ofingredients used in the specification and claims are to be understood asbeing modified in all instances by the term “about”. Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification and attached claims are approximations that mayvary depending upon the desired properties to be obtained by the presentinvention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard variation found in theirrespective testing measurements.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between (andincluding) the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10.

In this application, the use of the singular includes the plural andplural encompasses singular, unless specifically stated otherwise. Forexample, and without limitation, this application refers to coatingcompositions that, in certain embodiments, comprise a “film-formingresin.” Such references to “a film-forming resin” is meant to encompasscoating compositions comprising one film-forming resin as well ascoating compositions that comprise a mixture of two or more film-formingresins. In addition, in this application, the use of “or” means “and/or”unless specifically stated otherwise, even though “and/or” may beexplicitly used in certain instances.

In certain embodiments, the present invention is directed to coatingcompositions that are substantially free of chromium containingmaterial. In other embodiments, the coating compositions of the presentinvention are completely free of such a material. As used herein, theterm “substantially free” means that the material being discussed ispresent in the composition, if at all, as an incidental impurity. Inother words, the material does not affect the properties of thecomposition. This means that, in certain embodiments of the presentinvention, the coating composition contains less than 2 weight percentof chromium containing material or, in some cases, less than 0.05 weightpercent of chromium containing material, wherein such weight percentsare based on the total weight of the composition. As used herein, theterm “completely free” means that the material is not present in thecomposition at all. Thus, certain embodiments of the coatingcompositions of the present invention contain no chromium-containingmaterial. As used herein, the term “chromium containing material” refersto materials that include a chromium trioxide group, CrO₃. Non-limitingexamples of such materials include chromic acid, chromium trioxide,chromic acid anhydride, dichromate salts, such as ammonium dichromate,sodium dichromate, potassium dichromate, and calcium, barium, magnesium,zinc, cadmium, and strontium dichromate.

Certain embodiments of the coating compositions of the present inventionare substantially free of other undesirable materials, including heavymetals, such as lead and nickel. In certain embodiments, the coatingcompositions of the present invention are completely free of suchmaterials.

As indicated, the coating compositions of the present invention comprise“corrosion resisting particles.” As used herein, the term “corrosionresisting particles” refers to particles which, when included in acoating composition that is deposited upon a substrate, act to provide acoating that resists or, in some cases, even prevents, the alteration ordegradation of the substrate, such as by a chemical or electrochemicaloxidizing process, including rust in iron containing substrates anddegradative oxides in aluminum substrates.

In certain embodiments, the present invention is directed to coatingcompositions that comprise corrosion resisting particles comprising aninorganic oxide, in some embodiments a plurality of inorganic oxides,such as, for example, zinc oxide (ZnO), magnesium oxide (MgO), ceriumoxide (CeO₂), molybdenum oxide (MoO₃), and/or silicon dioxide (SiO₂),among others. As used herein, the term “plurality” means two or more.Therefore, certain embodiments of coating compositions of the presentinvention comprise corrosion resisting particles comprising two, three,four, or more than four inorganic oxides. In certain embodiments, theseinorganic oxides are present in such particles, for example, in the formof a homogeneous mixture or a solid-state solution of the plurality ofoxides.

In certain embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprising an inorganicoxide, or, in certain embodiments, a plurality thereof, comprise anoxide of zinc, cerium, yttrium, manganese, magnesium, molybdenum,lithium, aluminum, magnesium, tin, or calcium. In certain embodiments,the particles comprise an oxide of magnesium, zinc, cerium, or calcium.In certain embodiments, the particles also comprise an oxide of boron,phosphorous, silicon, zirconium, iron, or titanium. In certainembodiments, the particles comprise silicon dioxide (hereinafteridentified as “silica”).

In certain embodiments, the corrosion resisting particles that areincluded within certain embodiments of the coating compositions of thepresent invention comprise a plurality of inorganic oxides selected from(i) particles comprising an oxide of cerium, zinc, and silicon; (ii)particles comprising an oxide of calcium, zinc and silicon; (iii)particles comprising an oxide of phosphorous, zinc and silicon; (iv)particles comprising an oxide of yttrium, zinc, and silicon; (v)particles comprising an oxide of molybdenum, zinc, and silicon; (vi)particles comprising an oxide of boron, zinc, and silicon; (vii)particles comprising an oxide of cerium, aluminum, and silicon, (viii)particles comprising oxides of magnesium or tin and silicon, and (ix)particles comprising an oxide of cerium, boron, and silicon, or amixture of two or more of particles (i) to (ix).

In certain embodiments, the corrosion resisting particles included inthe coating compositions of the present invention are substantiallyfree, or, in some cases, completely free of an oxide of zirconium. Incertain embodiments, this means that the corrosion resisting particlescontain less than 1 percent by weight zirconium oxide or, in some cases,less than 0.05 percent by weight zirconium oxide, wherein such weightpercents are based on the total weight of the particle.

In certain embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 10 to 25 percentby weight zinc oxide, 0.5 to 25 percent by weight cerium oxide, and 50to 89.5 percent by weight silica, wherein the percents by weight arebased on the total weight of the particle. In certain embodiments, suchparticles are substantially free, or, in some cases, completely free ofzirconium.

In other embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 10 to 25 percentby weight zinc oxide, 0.5 to 25 percent by weight calcium oxide, and 50to 89.5 percent by weight silica, wherein the percents by weight arebased on the total weight of the particle. In certain embodiments, suchparticles are substantially free, or, in some cases, completely free ofzirconium.

In still other embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 10 to 25 percentby weight zinc oxide, 0.5 to 25 percent by weight yttrium oxide, and 50to 89.5 percent by weight silica, wherein the percents by weight arebased on the total weight of the particle. In certain embodiments, suchparticles are substantially free, or, in some cases, completely free ofzirconium.

In yet other embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 10 to 25 percentby weight zinc oxide, 0.5 to 50 percent by weight phosphorous oxide, and25 to 89.5 percent by weight silica, wherein the percents by weight arebased on the total weight of the particle. In certain embodiments, suchparticles are substantially free, or, in some cases, completely free ofzirconium.

In some embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 10 to 25 percentby weight zinc oxide, 0.5 to 50 percent by weight boron oxide, and 25 to89.5 percent by weight silica, wherein the percents by weight are basedon the total weight of the particle. In certain embodiments, suchparticles are substantially free, or, in some cases, completely free ofzirconium.

In certain embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 10 to 25 percentby weight zinc oxide, 0.5 to 50 percent by weight molybdenum oxide, and25 to 89.5 percent by weight silica, wherein the percents by weight arebased on the total weight of the particle. In certain embodiments, suchparticles are substantially free, or, in some cases, completely free ofzirconium.

In other embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 0.5 to 25 percentby weight cerium oxide, 0.5 to 50 percent by weight boron oxide, and 25to 99 percent by weight silica, wherein the percents by weight are basedon the total weight of the particle. In certain embodiments, suchparticles are substantially free, or, in some cases, completely free ofzirconium.

In still other embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 0.5 to 25 percentby weight cerium oxide, 0.5 to 50 percent by weight aluminum oxide, and25 to 99 percent by weight silica, wherein the percents by weight arebased on the total weight of the particle. In certain embodiments, suchparticles are substantially free, or, in some cases, completely free ofzirconium.

In yet other embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 0.5 to 25 percentby weight cerium oxide, 0.5 to 25 percent by weight zinc oxide, 0.5 to25 percent by weight boron oxide, and 25 to 98.5 percent by weightsilica, wherein the percents by weight are based on the total weight ofthe particle. In certain embodiments, such particles are substantiallyfree, or, in some cases, completely free of zirconium.

In certain embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 0.5 to 25 percentby weight yttrium oxide, 0.5 to 25 percent by weight phosphorous oxide,0.5 to 25 percent by weight zinc oxide, and 25 to 98.5 percent by weightsilica, wherein the percents by weight are based on the total weight ofthe particle. In certain embodiments, such particles are substantiallyfree, or, in some cases, completely free of zirconium.

In certain embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 0.5 to 75 percentby weight magnesium or tin oxide, and 25 to 99.5 percent by weightsilica, wherein the percents by weight are based on the total weight ofthe particle. In certain embodiments, such particles are substantiallyfree, or, in some cases, completely free of zirconium.

In some embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise 0.5 to 5 percentby weight yttrium oxide, 0.5 to 5 percent by weight molybdenum oxide,0.5 to 25 percent by weight zinc oxide, 0.5 to 5 percent by weightcerium oxide and 60 to 98 percent by weight silica, wherein the percentsby weight are based on the total weight of the particles. In certainembodiments, such particles are substantially free, or, in some cases,completely free of zirconium.

Certain embodiments of the coating compositions of the present inventioncomprise ultrafine corrosion resisting particles comprising an inorganicoxide, or in some embodiments, a plurality of inorganic oxides. As usedherein, the term “ultrafine” refers to particles that have a B.E.T.specific surface area of at least 10 square meters per gram, such as 30to 500 square meters per gram, or, in some cases, 80 to 250 squaremeters per gram. As used herein, the term “B.E.T. specific surface area”refers to a specific surface area determined by nitrogen adsorptionaccording to the ASTMD 3663-78 standard based on theBrunauer-Emmett-Teller method described in the periodical “The Journalof the American Chemical Society”, 60, 309 (1938).

In certain embodiments, the coating compositions of the presentinvention comprise corrosion resisting particles having a calculatedequivalent spherical diameter of no more than 200 nanometers, such as nomore than 100 nanometers, or, in certain embodiments, 5 to 50nanometers. As will be understood by those skilled in the art, acalculated equivalent spherical diameter can be determined from theB.E.T. specific surface area according to the following equation:

Diameter (nanometers)=6000/[BET(m²/g)*ρ(grams/cm³)]

Certain embodiments of the coating compositions of the present inventioncomprise corrosion resisting particles having an average primaryparticle size of no more than 100 nanometers, such as no more than 50nanometers, or, in certain embodiments, no more than 20 nanometers, asdetermined by visually examining a micrograph of a transmission electronmicroscopy (“TEM”) image, measuring the diameter of the particles in theimage, and calculating the average primary particle size of the measuredparticles based on magnification of the TEM image. One of ordinary skillin the art will understand how to prepare such a TEM image and determinethe primary particle size based on the magnification and the Examplescontained herein illustrate a suitable method for preparing a TEM image.The primary particle size of a particle refers to the smallest diametersphere that will completely enclose the particle. As used herein, theterm “primary particle size” refers to the size of an individualparticle as opposed to an agglomeration of two or more individualparticles.

In certain embodiments, the corrosion resisting particles have anaffinity for the medium of the composition sufficient to keep theparticles suspended therein. In these embodiments, the affinity of theparticles for the medium is greater than the affinity of the particlesfor each other, thereby reducing or eliminating agglomeration of theparticles within the medium.

The shape (or morphology) of the corrosion resisting particles can vary.For example, generally spherical morphologies can be used, as well asparticles that are cubic, platy, or acicular (elongated or fibrous).

The ultrafine corrosion resisting particles that are included in certainembodiments of the coating compositions of the present invention may beprepared by various methods, including gas phase synthesis processes,such as, for example, flame pyrolysis, hot walled reactor, chemicalvapor synthesis, among other methods. In certain embodiments, however,such particles are prepared by reacting together one or moreorganometallic and/or metal oxide precursors in a fast quench plasmasystem. In certain embodiments, the particles may be formed in such asystem by: (a) introducing materials into a plasma chamber; (b) rapidlyheating the materials by means of a plasma to yield a gaseous productstream; (c) passing the gaseous product stream through a restrictiveconvergent-divergent nozzle to effect rapid cooling and/or utilizing analternative cooling method, such as a cool surface or quenching stream,and (d) condensing the gaseous product stream to yield ultrafine solidparticles. Certain suitable fast quench plasma systems and methods fortheir use are described in U.S. Pat. Nos. 5,749,937, 5,935,293, andRE37,853 E, which are incorporated herein by reference. One particularprocess of preparing ultrafine corrosion resisting particles suitablefor use in certain embodiments of the coating compositions of thepresent invention comprises: (a) introducing one or more organometallicprecursors and/or inorganic oxide precursors into one axial end of aplasma chamber; (b) rapidly heating the precursor stream by means of aplasma as the precursor stream flows through the plasma chamber,yielding a gaseous product stream; (c) passing the gaseous productstream through a restrictive convergent-divergent nozzle arrangedcoaxially within the end of the reaction chamber; and (d) subsequentlycooling and slowing the velocity of the desired end product exiting fromthe nozzle, yielding ultrafine solid particles.

The precursor stream may be introduced to the plasma chamber as a solid,liquid, gas, or a mixture thereof. Suitable liquid precursors that maybe used as part of the precursor stream include organometallics, suchas, for example, cerium-2 ethylhexanoate, zinc-2 ethylhexanoate,tetraethoxysilane, calcium methoxide, triethylphosphate, lithium 2,4pentanedionate, yttrium butoxide, molybdenum oxidebis(2,4-pentanedionate), trimethoxyboroxine, aluminum sec-butoxide,among other materials, including mixtures thereof. Suitable solidprecursors that may be used as part of the precursor stream includesolid silica powder (such as silica fume, fumed silica, silica sand,and/or precipitated silica), cerium acetate, cerium oxide, magnesiumoxide, tin oxide, zinc oxide, and other oxides, among other materials,including mixtures thereof.

In certain embodiments, the ultrafine corrosion resisting particles thatare included in certain embodiments of the coating compositions of thepresent invention are prepared by a method comprising: (a) introducing asolid precursor into a plasma chamber; (b) heating the precursor bymeans of a plasma to a selected reaction temperature as the precursorflows through the plasma chamber, yielding a gaseous product stream; (c)contacting the gaseous product stream with a plurality of quench streamsinjected into the plasma chamber through a plurality of quench gasinjection ports, wherein the quench streams are injected at flow ratesand injection angles that result in the impingement of the quenchstreams with each other within the gaseous product stream, therebyproducing ultrafine solid particles; and (d) passing the ultrafine solidparticles through a converging member.

Referring now to FIG. 1, there is seen a flow diagram depicting certainembodiments of the methods for making ultrafine corrosion resistingparticles in accordance with the present invention. As is apparent, incertain embodiments, at step 100, a solid precursor is introduced into afeed chamber. Then, as is apparent from FIG. 1 at step 200, in certainembodiments, the solid precursor is contacted with a carrier. Thecarrier may be a gas that acts to suspend the solid precursor in thegas, thereby producing a gas-stream suspension of the solid precursor.Suitable carrier gasses include, but are not limited to, argon, helium,nitrogen, oxygen, air, hydrogen, or a combination thereof.

Next, in certain embodiments, the solid precursor is heated, at step300, by means of a plasma as the solid precursor flows through theplasma chamber, yielding a gaseous product stream. In certainembodiments, the precursor is heated to a temperature ranging from2,500° to 20,000° C., such as 1,700° to 8,000° C.

In certain embodiments, the gaseous product stream may be contacted witha reactant, such as a hydrogen-containing material, that may be injectedinto the plasma chamber, as indicated at step 350. The particularmaterial used as the reactant is not limited and may include, forexample, air, water vapor, hydrogen gas, ammonia, and/or hydrocarbons,depending on the desired properties of the resulting ultrafine solidparticles.

As is apparent from FIG. 1, in certain embodiments, after the gaseousproduct stream is produced, it is, at step 400, contacted with aplurality of quench streams that are injected into the plasma chamberthrough a plurality of quench stream injection ports, wherein the quenchstreams are injected at flow rates and injection angles that result inimpingement of the quench streams with each other within the gaseousproduct stream. The material used in the quench streams is not limited,so long as it adequately cools the gaseous product stream to causeformation of ultrafine solid particles. Materials suitable for use inthe quench streams include, but are not limited to, hydrogen gas, carbondioxide, air, water vapor, ammonia, mono, di and polybasic alcohols,silicon-containing materials (such as hexamethyldisilazane), carboxylicacids and/or hydrocarbons.

The particular flow rates and injection angles of the various quenchstreams are not limited, so long as they impinge with each other withinthe gaseous product stream to result in the rapid cooling of the gaseousproduct stream to produce ultrafine solid particles. This differentiatesthe present invention from certain fast quench plasma systems thatutilize Joule-Thompson adiabatic and isoentropic expansion through, forexample, the use of a converging-diverging nozzle or a “virtual”converging diverging nozzle, to form ultrafine particles. In the presentinvention, the gaseous product stream is contacted with the quenchstreams to produce ultrafine solid particles before passing thoseparticles through a converging member, such as, for example, aconverging-diverging nozzle, which the inventors have surprisinglydiscovered aids in, inter alia, reducing the fouling or clogging of theplasma chamber, thereby enabling the production of ultrafine solidparticles from solid reactants without frequent disruptions in theproduction process for cleaning of the plasma system. In the presentinvention, the quench streams primarily cool the gaseous product streamthrough dilution, rather than adiabatic expansion, thereby causing arapid quenching of the gaseous product stream and the formation ofultrafine solid particles prior to passing the particles into andthrough a converging member, such as a converging-diverging nozzle, asdescribed below.

Referring again to FIG. 1, it is seen that, after contacting the gaseousproduct stream with the quench streams to cause production of ultrafinesolid particles, the particles are, at step 500, passed through aconverging member, wherein the plasma system is designed to minimize thefouling thereof. In certain embodiments, the converging member comprisesa converging-diverging (De Laval) nozzle. In these embodiments, whilethe convergent-divergent nozzle may act to cool the product stream tosome degree, the quench streams perform much of the cooling so that asubstantial amount of ultrafine solid particles are formed upstream ofthe convergent-divergent nozzle. In these embodiments, theconvergent-divergent nozzle may primarily act as a choke position thatpermits operation of the plasma chamber at higher pressures, therebyincreasing the residence time of the materials therein. The combinationof quench stream dilution cooling with a convergent-divergent nozzleappears to provide a commercially viable method of producing ultrafinesolid particles from solid precursors, since, for example, (i) a solidprecursor can be used effectively without heating the feed material to agaseous or liquid state before injection into the plasma, and (ii)fouling of the plasma system can be minimized, or eliminated, therebyreducing or eliminating disruptions in the production process forcleaning of the plasma system.

As is seen in FIG. 1, in certain embodiments of the methods of thepresent invention, after the ultrafine solid particles are passedthrough a converging member, they are harvested at step 600. Anysuitable means may be used to separate the ultrafine solid particlesfrom the gas flow, such as, for example, a bag filter or cycloneseparator.

Now referring to FIG. 2, there is depicted a schematic diagram of anapparatus for producing ultrafine solid particles in accordance withcertain embodiments of the present invention. As is apparent, a plasmachamber 20 is provided that includes a solid particle feed inlet 50.Also provided is at least one carrier gas feed inlet 14, through which acarrier gas flows in the direction of arrow 30 into the plasma chamber20. As previously indicated, the carrier gas acts to suspend the solidreactant in the gas, thereby producing a gas-stream suspension of thesolid reactant which flows towards plasma 29. Numerals 23 and 25designate cooling inlet and outlet respectively, which may be presentfor a double-walled plasma chamber 20. In these embodiments, coolantflow is indicated by arrows 32 and 34.

In the embodiment depicted by FIG. 2, a plasma torch 21 is provided.Torch 21 vaporizes the incoming gas-stream suspension of solid reactantwithin the resulting plasma 29 as the stream is delivered through theinlet of the plasma chamber 20, thereby producing a gaseous productstream. As is seen in FIG. 2, the solid particles are, in certainembodiments, injected downstream of the location where the arc attachesto the annular anode 13 of the plasma generator or torch.

A plasma is a high temperature luminous gas which is at least partially(1 to 100%) ionized. A plasma is made up of gas atoms, gas ions, andelectrons. A thermal plasma can be created by passing a gas through anelectric arc. The electric arc will rapidly heat the gas to very hightemperatures within microseconds of passing through the arc. The plasmais often luminous at temperatures above 9000 K.

A plasma can be produced with any of a variety of gases. This can giveexcellent control over any chemical reactions taking place in the plasmaas the gas may be inert, such as argon, helium, or neon, reductive, suchas hydrogen, methane, ammonia, and carbon monoxide, or oxidative, suchas oxygen, nitrogen, and carbon dioxide. Air, oxygen, and/oroxygen/argon gas mixtures are often used to produce ultrafine solidparticles in accordance with the present invention. In FIG. 2, theplasma gas feed inlet is depicted at 31.

As the gaseous product stream exits the plasma 29 it proceeds towardsthe outlet of the plasma chamber 20. As is apparent, an additionalreactant, as described earlier, can be injected into the reactionchamber prior to the injection of the quench streams. A supply inlet forthe reactant is shown in FIG. 2 at 33.

As is seen in FIG. 2, in certain embodiments of the present invention,the gaseous product stream is contacted with a plurality of quenchstreams which enter the plasma chamber 20 in the direction of arrows 41through a plurality of quench gas injection ports 40 located along thecircumference of the plasma chamber 20. As previously indicated, theparticular flow rate and injection angle of the quench streams is notlimited so long as they result in impingement of the quench streams 41with each other within the gaseous reaction product stream, in somecases at or near the center of the gaseous product stream, to result inthe rapid cooling of the gaseous product stream to produce ultrafinesolid particles. This results in a quenching of the gaseous productstream through dilution to form ultrafine solid particles.

Referring now to FIG. 3, there is depicted a perspective view of aplurality of quench gas injection ports 40 in accordance with certainembodiments of the present invention. In this particular embodiment, six(6) quench gas injection ports are depicted, wherein each port disposedat an angle “θ” apart from each other along the circumference of thereactor chamber 20. It will be appreciated that “θ” may have the same ora different value from port to port. In certain embodiments of thepresent invention, at least four (4) quench stream injection ports 40are provided, in some cases at least six (6) quench stream injectionports are present or, in other embodiments, twelve (12) or more quenchstream injection ports are present. In certain embodiments, each angle“θ” has a value of no more than 90°. In certain embodiments, the quenchstreams are injected into the plasma chamber normal (90° angle) to theflow of the gaseous reaction product. In some cases, however, positiveor negative deviations from the 90° angle by as much as 30° may be used.

In certain methods of the present invention, contacting the gaseousproduct stream with the quench streams results in the formation ofultrafine solid particles, which are then passed into and through aconverging member. As used herein, the term “converging member” refersto a device that restricts passage of a flow therethrough, therebycontrolling the residence time of the flow in the plasma chamber due topressure differential upstream and downstream of the converging member.

In certain embodiments, the converging member comprises aconvergent-divergent (De Laval) nozzle, such as that which is depictedin FIG. 2, which is positioned within the outlet of the reactor chamber20. The converging or upstream section of the nozzle, i.e., theconverging member, restricts gas passage and controls the residence timeof the materials within the plasma chamber 20. It is believed that thecontraction that occurs in the cross sectional size of the gaseousstream as it passes through the converging portion of nozzle 22 changesthe motion of at least some of the flow from random directions,including rotational and vibrational motions, to a straight line motionparallel to the reaction chamber axis. In certain embodiments, thedimensions of the plasma chamber 20 and the material are selected toachieve sonic velocity within the restricted nozzle throat.

As the confined stream of flow enters the diverging or downstreamportion of the nozzle 22, it is subjected to an ultra fast decrease inpressure as a result of a gradual increase in volume along the conicalwalls of the nozzle exit. By proper selection of nozzle dimensions, theplasma chamber 20 can be operated at atmospheric pressure, or slightlyless than atmospheric pressure, or, in some cases, at a pressurizedcondition, to achieve the desired residence time, while the chamber 26downstream of the nozzle 22 is maintained at a vacuum pressure byoperation of a vacuum producing device, such as a vacuum pump 60.Following passage through nozzle 22, the ultrafine solid particles maythen enter a cool down chamber 26.

As is apparent from FIG. 2, in certain embodiments of the presentinvention, the ultrafine solid particles may flow from cool down chamber26 to a collection station 27 via a cooling section 45, which maycomprise, for example, a jacketed cooling tube. In certain embodiments,the collection station 27 comprises a bag filter or other collectionmeans. A downstream scrubber 28 may be used if desired to condense andcollect material within the flow prior to the flow entering vacuum pump60.

In certain embodiments, the residence times for materials within theplasma chamber 20 are on the order of milliseconds. The solid precursormay be injected under pressure (such as greater than 1 to 100atmospheres) through a small orifice to achieve sufficient velocity topenetrate and mix with the plasma. In addition, in many cases theinjected stream of solid precursor is injected normal (90° angle) to theflow of the plasma gases. In some cases, positive or negative deviationsfrom the 90° angle by as much as 30° may be desired.

The high temperature of the plasma rapidly vaporizes the solidprecursor. There can be a substantial difference in temperaturegradients and gaseous flow patterns along the length of the plasmachamber 20. It is believed that, at the plasma arc inlet, flow isturbulent and there is a high temperature gradient; from temperatures ofabout 20,000 K at the axis of the chamber to about 375 K at the chamberwalls. At the nozzle throat, it is believed, the flow is laminar andthere is a very low temperature gradient across its restricted openarea.

The plasma chamber is often constructed of water cooled stainless steel,nickel, titanium, copper, aluminum, or other suitable materials. Theplasma chamber can also be constructed of ceramic materials to withstanda vigorous chemical and thermal environment.

The plasma chamber walls may be internally heated by a combination ofradiation, convection, and conduction. In certain embodiments, coolingof the plasma chamber walls prevents unwanted melting and/or corrosionat their surfaces. The system used to control such cooling shouldmaintain the walls at as high a temperature as can be permitted by theselected wall material, which often is inert to the materials within theplasma chamber at the expected wall temperatures. This is true also withregard to the nozzle walls, which may be subjected to heat by convectionand conduction.

The length of the plasma chamber is often determined experimentally byfirst using an elongated tube within which the user can locate thetarget threshold temperature. The plasma chamber can then be designedlong enough so that precursors have sufficient residence time at thehigh temperature to reach an equilibrium state and complete theformation of the desired end products.

The inside diameter of the plasma chamber 20 may be determined by thefluid properties of the plasma and moving gaseous stream. It should besufficiently great to permit necessary gaseous flow, but not so largethat recirculating eddys or stagnant zones are formed along the walls ofthe chamber. Such detrimental flow patterns can cool the gasesprematurely and precipitate unwanted products. In many cases, the insidediameter of the plasma chamber 20 is more than 100% of the plasmadiameter at the inlet end of the plasma chamber.

In certain embodiments, the converging section of the nozzle has a highaspect ratio change in diameter that maintains smooth transitions to afirst steep angle (such as >45°) and then to lesser angles (such as <45°degree.) leading into the nozzle throat. The purpose of the nozzlethroat is often to compress the gases and achieve sonic velocities inthe flow. The velocities achieved in the nozzle throat and in thedownstream diverging section of the nozzle are controlled by thepressure differential between the plasma chamber and the sectiondownstream of the diverging section of the nozzle. Negative pressure canbe applied downstream or positive pressure applied upstream for thispurpose. A converging-diverging nozzle of the type suitable for use inthe present invention is described in U.S. Pat. No. RE37,853 at col. 9,line 65 to col. 11, line 32, the cited portion of which beingincorporated by reference herein.

It has been surprisingly discovered that the methods and apparatus formaking ultrafine solid particles of the present invention, which utilizequench gas dilution cooling in combination with a converging member,such as a converging-diverging nozzle, has several benefits. First, sucha combination allows for the use of sufficient residence times of solidmaterial within the plasma system that make the use of solid precursorspractical. Second, because ultrafine solid particles are formed prior tothe flow reaching the converging member, fouling of the plasma chamberis reduced or, in some cases, even eliminated, since the amount ofmaterial sticking to the interior surface of the converging member isreduced or, in some cases, eliminated. Third, this combination allowsfor the collection of ultrafine solid particles at a single collectionpoint, such as a filter bag, with a minimal amount of such particlesbeing deposited within the cooling chamber or cooling section describedearlier.

In certain embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise an inorganic oxidenetwork comprising one or more inorganic materials. As used herein, theterm “inorganic oxide network comprising one or more inorganicmaterials” refers to a molecular chain comprising one, or, in somecases, two or more different inorganic materials chemically connected toeach other through one or more oxygen atoms. Such a network may beformed from hydrolysis of metal salts, examples of which include, butare not limited to, Ce^(3+,) Ce⁴⁺, Zn²⁺, Mg²⁺, Y³⁺, Ca²⁺, Mn⁷⁺, andMo⁶⁺. In certain embodiments, the inorganic oxide network compriseszinc, cerium, yttrium, manganese, magnesium, or calcium. In certainembodiments, the inorganic oxide network also comprises silicon,phosphorous, and/or boron. In certain embodiments, the inorganic oxidenetwork comprises cerium, zinc, zirconium, and/or manganese, as well assilicon. In certain embodiments, the inorganic oxide network comprises0.5 to 30 percent by weight cerium and 0.5 to 20 percent by weight zinc,with the weight percents being based on the total weight of thematerial.

In certain embodiments, the inorganic oxide network comprises siliconresulting from the hydrolysis of an organosilane, such as silanescomprising two, three, four, or more alkoxy groups. Specific examples ofsuitable organosilanes include methyltrimethoxysilane,methyltriethoxysilane, methyltrimethoxysilane, methyltriacetoxysilane,methyltripropoxysilane, methyltributoxysilane, ethyltrimethoxysilane,ethyltriethoxysilane, γ-meth-acryloxypropyltrimethoxysilane,γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane,γ-mercaptopropyltrimethoxysilane, chloromethyltrimethoxysilane,chloromethytriethoxysilane, dimethyldiethoxysilane,γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane,tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane,tetra-n-butoxysilane, glycidoxymethyltriethoxysilane,α-glycidoxyethyltrimethoxysilane, α-glycidoxyethyltriethoxysilane,β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane,α-glycidoxy-propyltrimethoxysilane, α-glycidoxypropyltriethoxysilane,β-glycidoxypropyltrimethoxysilane, β-glycidoxypropyltriethoxysilane,γ-glycidoxypropyltrimethoxysilane,γ-glycidoxypropylmethyldimethoxysilane,γ-glycidoxy-propyldimethylethoxysilane, hydrolyzates thereof, oligomersthereof and mixtures of such silane monomers. In certain embodiments,the inorganic oxide network comprises silicon resulting from a silicate,such as potassium silicate, sodium silicate, and/or ammonium silicate.

In certain embodiments, the inorganic oxide network is formed bycombining one, or in some cases, two or more metal salts, such as metalacetates, chlorides, sulfates, and/or nitrates, with water to produce ahydrolyzed species comprising a polyvalent metal ion. The hydrolyzedspecies is then reacted with a suitable silicon compound (or phosphorousor boron as the case may be) to produce an inorganic oxide networkcomprising one or more inorganic materials. The resulting solid materialmay then be filtered, washed, and dried. The resulting dried powder may,if desired, be calcined at a temperature of, for example, 200 to 1,000°F. The Examples herein illustrate suitable methods for making suchcorrosion resisting particles.

In certain embodiments, the corrosion resisting particles comprising aninorganic oxide network, as described above, are ultrafine particles.

In certain embodiments of the coating compositions of the presentinvention, the corrosion resisting particles comprise a clay. In certainembodiments, such clays are treated with a lanthanide and/or transitionmetal salt. Suitable clays include, for example, layer structuredLaponite® (a hydrous sodium lithium magnesium silicate modified withtetra sodium pyrophosphate commercially available from Southern ClayProducts, Inc.) and bentonite (an aluminum phyllosilicate generallyimpure clay consisting mostly of montmorillonite,(Na,Ca)_(0.33)(Al,Mg)₂Si₄O₁₀(OH)₂.nH₂O).

Such corrosion resisting particles may be produced by adding a clay,such as the layer structured Laponite® referenced above, to a stirreddilute solution of a metal salt (up to 50% by weight metal), such as,for example, cerium acetate or zinc acetate, in water and filtering offthe resulting solid precipitate. The solid precipitate may, if desired,be washed, such as with water and/or acetone, and dried.

In certain embodiments, the present invention is directed to coatingcompositions that comprise corrosion resisting particles comprising aninorganic oxide in combination with a pH buffering agent, such as, forexample, a borate. As used herein, the term “pH buffering agent” ismeant to refer to a material that adjusts the pH of the inorganic oxideto a level higher than the pH would be in the absence of the material.In certain embodiments, such corrosion resisting particles comprise amixed metal oxide that includes borate (B₂O₃), and one or more oxides ofzinc, barium, cerium, yttrium, magnesium, molybdenum, lithium, aluminum,or calcium. In certain embodiments, such a mixed oxide is deposited onand/or within a support.

As used herein, the term “support” refers to a material upon which or inwhich another material is carried. In certain embodiments, the corrosionresisting particles comprise an inorganic oxide, a borate, and a silicasupport, such as fumed silica, commercially available under thetradename Aerosil® from Degussa, or precipitated silica, such as Hi-Sil®T600 from PPG Industries, Pittsburgh, Pa. In certain embodiments, thesupport has an average primary particle size of no more than 20nanometers. In certain embodiments, such corrosion resisting particlesprovide desirable protection against both edge corrosion andscribe-corrosion on the surface of a substrate that is exposed to anodicdissolution.

Specific non-limiting examples of suitable corrosion resisting particlescomprising a mixed metal oxide including borate comprise CaO.B₂O₃,BaO.B₂O₃, ZnO.B₂O₃, and/or MgO.B₂O₃. Such corrosion resisting pigmentscan be produced, for example, by precipitating the such materials on thesupport. Such precipitation may be conducted by, for example, combiningboric acid and one or more precursor materials comprising zinc, barium,cerium, yttrium, magnesium, molybdenum, lithium, aluminum, or calcium,with a slurry of water and silica, evaporating the water, and thencalcining the resulting material to produce the corrosion resistingparticles, which may then be milled to a desired particle size.

In certain embodiments, such particles may also comprise additionalmaterials, such as phosphates, silicates, hydroxy-phosphates, and/orhydroxy-silicates of a metal, such as zinc or aluminum.

In certain embodiments, one or more of the previously describedcorrosion resisting particles are present in the coating compositions ofthe present invention in an amount of 3 to 50 percent by volume, such as8 to 30 percent by volume, or, in certain embodiments, 10 to 18 percentby volume, wherein the volume percents are based on the total volume ofthe coating composition.

In certain embodiments, the coating compositions of the presentinvention comprise corrosion resisting particles comprising chemicallymodified particles having an average primary particle size of no morethan 500 nanometers, in some cases, no more than 200 nanometers, and, inyet other cases, no more than 100 nanometers. Examples of such particlesare described in U.S. Pat. No. 6,790,904 at col. 3, line 43 to col. 8,line 46; United States Patent Application Publication No. 2003/0229157A1 at [0021] to [0048]; U.S. Pat. No. 6,835,458 at col. 4, line 54 tocol. 7, line 58; and U.S. Pat. No. 6,593,417 at col. 23, line 48 to col.24, line 32, the cited portions of which being incorporated by referenceherein. Suitable chemically modified particles are also commerciallyavailable, such as those available under the tradename NANOBYK-3650,from Byk-Chemie.

While such chemically modified particles are known in the art forproviding mar and/or scratch resistance properties to coatingcompositions into which they are incorporated, the present inventorshave surprisingly discovered that they also impart corrosion resistanceproperties to metal substrate primer compositions, such as etch-primers,and/or pretreatment coating compositions when such compositions areapplied to a bare metal substrate. In fact, the inventors havediscovered that, even when such chemically-modified particles areincluded in a coating composition in relatively small amounts, i.e.,particle to film-forming binder weight ratios of less than 0.2, thecoating composition, when deposited onto at least a portion of a baremetal substrate selected from cold rolled steel, electrogalvanized steeland aluminum and cured, sometimes produces a substrate that exhibitscorrosion resistance properties similar to, or, in some cases, greaterthan, the corrosion resistance properties the same substrate exhibitswhen at least partially coated under the same conditions with aconventional chrome-containing corrosion-resistant composition (asdescribed in more detail below). As a result, the inventors havediscovered that such corrosion resisting particles can be used toreplace chromium in metal substrate primer coating compositions, such asetch-primers, and/or metal pretreatment coating compositions.

As previously indicated, in certain embodiments, the coatingcompositions of the present invention comprise a film-forming resin. Asused herein, the term “film-forming resin” refers to resins that canform a self-supporting continuous film on at least a horizontal surfaceof a substrate upon removal of any diluents or carriers present in thecomposition or upon curing at ambient or elevated temperature.

Film-forming resins that may be used in the coating compositions of thepresent invention include, without limitation, those used in automotiveOEM coating compositions, automotive refinish coating compositions,industrial coating compositions, architectural coating compositions,coil coating compositions, and aerospace coating compositions, amongothers.

In certain embodiments, the film-forming resin included within thecoating compositions of the present invention comprises a thermosettingfilm-forming resin. As used herein, the term “thermosetting” refers toresins that “set” irreversibly upon curing or crosslinking, wherein thepolymer chains of the polymeric components are joined together bycovalent bonds. This property is usually associated with a cross-linkingreaction of the composition constituents often induced, for example, byheat or radiation. See Hawley, Gessner G., The Condensed ChemicalDictionary, Ninth Edition., page 856; Surface Coatings, vol. 2, Oil andColour Chemists' Association, Australia, TAFE Educational Books (1974).Curing or crosslinking reactions also may be carried out under ambientconditions. Once cured or crosslinked, a thermosetting resin will notmelt upon the application of heat and is insoluble in solvents. In otherembodiments, the film-forming resin included within the coatingcompositions of the present invention comprises a thermoplastic resin.As used herein, the term “thermoplastic” refers to resins that comprisepolymeric components that are not joined by covalent bonds and therebycan undergo liquid flow upon heating and are soluble in solvents. SeeSaunders, K.J., Organic Polymer Chemistry, pp. 41-42, Chapman and Hall,London (1973).

Film-forming resins suitable for use in the coating compositions of thepresent invention include, for example, those formed from the reactionof a polymer having at least one type of reactive group and a curingagent having reactive groups reactive with the reactive group(s) of thepolymer. As used herein, the term “polymer” is meant to encompassoligomers, and includes, without limitation, both homopolymers andcopolymers. The polymers can be, for example, acrylic, saturated orunsaturated polyester, polyurethane or polyether, polyvinyl, cellulosic,acrylate, silicon-based polymers, co-polymers thereof, and mixturesthereof, and can contain reactive groups such as epoxy, carboxylic acid,hydroxyl, isocyanate, amide, carbamate and carboxylate groups, amongothers, including mixtures thereof.

Suitable acrylic polymers include, for example, those described inUnited States Patent Application Publication 2003/0158316 A1 at[0030]-[0039], the cited portion of which being incorporated herein byreference. Suitable polyester polymers include, for example, thosedescribed in United States Patent Application Publication 2003/0158316A1 at [0040]-[0046], the cited portion of which being incorporatedherein by reference. Suitable polyurethane polymers include, forexample, those described in United States Patent Application Publication2003/0158316 A1 at [0047]-[0052], the cited portion of which beingincorporated herein by reference. Suitable silicon-based polymers aredefined in U.S. Pat. No. 6,623,791 at col. 9, lines 5-10, the citedportion of which being incorporated herein by reference.

In certain embodiments of the present invention, the film-forming resincomprises a polyvinyl polymer, such as a polyvinyl butyral resin. Suchresins may be produced by reacting a polyvinyl alcohol with an aldehyde,such as acetaldehyde, formaldehyde, or butyraldehyde, among others.Polyvinyl alcohols may be produced by the polymerization of vinylacetate monomer and the subsequent, alkaline-catalyzed methanolysis ofthe polyvinyl acetate obtained. The acetalization reaction of polyvinylalcohol and butyraldehyde is not quantitative, so the resultingpolyvinyl butyral may contain a certain amount of hydroxyl groups. Inaddition, a small amount of acetyl groups may remain in the polymerchain.

Commercially available polyvinyl butyral resins may be used. Such resinsoften have an average degree of polymerization of 500 to 1000 and adegree of butyration of 57 to 70 mole percent. Specific examples ofsuitable polyvinyl butyral resins include the MOWITAL® line of polyvinylbutyral resins commercially available from Kuraray America, Inc., NewYork, N.Y. and the BUTVAR® polyvinyl butyral resins commerciallyavailable from Solutia Inc.

As indicated earlier, certain coating compositions of the presentinvention can include a film-forming resin that is formed from the useof a curing agent. As used herein, the term “curing agent” refers to amaterial that promotes “cure” of composition components. As used herein,the term “cure” means that any crosslinkable components of thecomposition are at least partially crosslinked. In certain embodiments,the crosslink density of the crosslinkable components, i.e., the degreeof crosslinking, ranges from 5 percent to 100 percent of completecrosslinking, such as 35 percent to 85 percent of complete crosslinking.One skilled in the art will understand that the presence and degree ofcrosslinking, i.e., the crosslink density, can be determined by avariety of methods, such as dynamic mechanical thermal analysis (DMTA)using a Polymer Laboratories MK III DMTA analyzer, as is described inU.S. Pat. No. 6,803,408, at col. 7, line 66 to col. 8, line 18, thecited portion of which being incorporated herein by reference.

Any of a variety of curing agents known to those skilled in the art maybe used. For example exemplary suitable aminoplast and phenoplast resinsare described in U.S. Pat. No. 3,919,351 at col. 5, line 22 to col. 6,line 25, the cited portion of which being incorporated herein byreference. Exemplary suitable polyisocyanates and blocked isocyanatesare described in U.S. Pat. No. 4,546,045 at col. 5, lines 16 to 38; andin U.S. Pat. No. 5,468,802 at col. 3, lines 48 to 60, the cited portionsof which being incorporated herein by reference. Exemplary suitableanhydrides are described in U.S. Pat. No. 4,798,746 at col. 10, lines 16to 50; and in U.S. Pat. No. 4,732,790 at col. 3, lines 41 to 57, thecited portions of which being incorporated herein by reference.Exemplary suitable polyepoxides are described in U.S. Pat. No. 4,681,811at col. 5, lines 33 to 58, the cited portion of which being incorporatedherein by reference. Exemplary suitable polyacids are described in U.S.Pat. No. 4,681,811 at col. 6, line 45 to col. 9, line 54, the citedportion of which being incorporated herein by reference. Exemplarysuitable polyols are described in U.S. Pat. No. 4,046,729 at col. 7,line 52 to col. 8, line 9 and col. 8, line 29 to col. 9, line 66, and inU.S. Pat. No. 3,919,315 at col. 2, line 64 to col. 3, line 33, the citedportions of which being incorporated herein by reference. Examplessuitable polyamines described in U.S. Pat. No. 4,046,729 at col. 6, line61 to col. 7, line 26, and in U.S. Pat. No. 3,799,854 at column 3, lines13 to 50, the cited portions of which being incorporated herein byreference. Appropriate mixtures of curing agents, such as thosedescribed above, may be used.

In certain embodiments, the coating compositions of the presentinvention comprise one or more polyacrylates and/or polythiols and, as aresult, are radiation curable. Examples of suitable polyacrylates arediacrylates and triacrylates. Specific examples include hexanedioldiacrylate or tripropyleneglycol diacrylate, triacrylates such astrimethylolpropane triacrylate, alkoxylated trimethylolpropanetriacrylate or pentaerythritol triacrylate, polyacrylates such aspentaerythritol tetraacrylate or dipentaerythritol hexaacrylate, epoxyacrylates obtained for example by reacting epoxides with acrylic acidsuch as UVE 100 and UVE 150 available from Croda or Actilane 320 orActilane 330 available from Akcros Chemicals, or unsaturated polyesterssuch as polyesters prepared with maleic anhydride as one of themonomeric components. In certain embodiments, the polyacrylate(s) ispresent in an amount of 50-80% by weight, such as 60 to 70% by weight,based on resin solids of the composition.

In certain embodiments, the polyacrylate contains a urethane moiety andis, therefore, a urethane polyacrylate, such as a urethane diacrylate.Urethane polyacrylates are typically prepared by reacting anisocyanate-functional compound with a hydroxyl-functional acrylate. Theurethane polyacrylate typically is present in amounts of 50 to 100, suchas 60 to 80 percent by weight, based on total weight of the radiationpolymerizable compound.

The polyisocyanate that is reacted with the hydroxy functional acrylatecan be any organic polyisocyanate. The polyisocyanate may be aromatic,aliphatic, cycloaliphatic, or heterocyclic and may be unsubstituted orsubstituted. Many such organic polyisocyanates are known, examples ofwhich include: toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, andmixtures thereof; diphenylmethane-4,4′-diisocyanate,diphenylmethane-2,4′-diisocyanate and mixtures thereof; o-, m- and/orp-phenylene diisocyanate; biphenyl diisocyanate;3,3′-dimethyl-4,4′-diphenylene diisocyanate; propane-1,2-diisocyanateand propane-1,3-diisocyanate; butane-1,4-diisocyanate;hexane-1,6-diisocyanate; 2,2,4-trimethylhexane-1,6-diisocyanate; lysinemethyl ester diisocyanate; bis(isocyanatoethyl) fumarate; isophoronediisocyanate; ethylene diisocyanate; dodecane-1,12-diisocyanate;cyclobutane-1,3-diisocyanate; cyclohexane-1,2-diisocyanate,cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate and mixturesthereof; methylcyclohexyl diisocyanate;hexahydrotoluene-2,4-diisocyanate; hexahydrotoluene-2,6-diisocyanate andmixtures thereof; hexahydrophenylene-1,3-diisocyanate;hexahydrophenylene-1,4-diisocyanate and mixtures thereof;perhydrodiphenylmethane-2,4′-diisocyanate,perhydrodiphenylmethane-4,4′-diisocyanate and mixtures thereof;4,4′-methylene bis(isocyanato cyclohexane) available from Mobay ChemicalCompany as Desmodur W; 3,3′-dichloro-4,4′-diisocyanatobiphenyl,tris(4-isocyanatophenyl)methane; 1,5-diisocyanatonaphthalene,hydrogenated toluene diisocyanate;1-isocyanatomethyl-5-isocyanato-1,3,3-trimethylcyclohexane and1,3,5-tris(6-isocyanatohexyl)-biuret.

Examples of hydroxyl-functional acrylates which can be reacted with thepolyisocyanate polyurethanes to form the urethane acrylates include:2-hydroxyethyl (meth)acrylate; glycerol di(meth)acrylate; the(meth)acrylates of the glycidyl ethers of butanol, bisphenol-A,butanediol, diethylene glycol, trimethylolpropane and other mono-, di-,tri- and polyhydric alcohols; the (meth)acrylates of epoxides such asstyrene oxide, 1-hexane oxide, 1-decene oxide, 1-butene oxide; the(meth)acrylates of epoxidized fatty acids such as linoleic and linolenicacid; the (meth)acrylates of epoxidized linseed and soya oils; 2- and3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate; andhalogenated hydroxyalkyl acrylates such as 3-chloro-2-hydroxypropyl(meth)acrylate; 3-bromo-2-hydroxypropyl (meth)acrylate;2-chloro-1-(hydroxymethyl)ethyl (meth)acrylate, and2-bromo-1-(hydroxymethyl)ethyl (meth)acrylate. Wherever used in thespecification and claims herein, it is to be understood that the term“acrylate” is intended to include “methacrylate” and may be expressed as(meth)acrylate.

Other useful hydroxyl-functional compounds having ethylenic unsaturationthat can be reacted with the polyisocyanate include allyl alcohol andderivatives thereof.

It should be understood that the hydroxyl-functional acrylates and thepolyisocyanates can be prereacted to form an isocyanate-functionalacrylate that is then reacted with a polyol to form the polyurethanepolyacrylate. Similarly, isocyanate-functional acrylates such asisocyanato ethyl acrylate can be reacted with a polyol to form thepolyurethane polyacrylate. Further, other ethylenically unsaturatedisocyanate-functional compounds such as vinyl isocyanate andallylisocyanate can be reacted with a polyol to form an ethylenicallyunsaturated polyurethane.

Examples of polyols are simple diols, triols, and higher hydricalcohols. Specific examples include 1,3-propanediol, 1,2-butanediol,1,3-butanediol, 1,4-butanediol, 2,3-butanediol,2,2,4-trimethyl-1,3-pentanediol, 1,5-pentanediol, 2,4-pentanediol,1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 2,4-heptanediol,1,8-octanediol, 1,9-nonanediol, 4,5-nonanediol, 1,10-decanediol,1,9-decanediol, 2-methyl-1,3-pentanediol, 2-methyl-2,4-pentanediol,2-ethyl-1,3-hexanediol, 2,2-dimethyl-1,3-propanediol,2-ethylbutane-1,4-diol, 2,2-diethylpropane-1,3-diol,2,2-dimethylpropane-1,3-diol, 3-methyl-pentane-1,4-diol,2,2-diethylbutane-1,3-diol, 1,1,1-trimethylolpropane, trimethylolethane,1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-bis(hydroxymethyl)cyclohexane, 1,2-bis(hydroxyethyl) cyclohexane, ethylene glycol,diethylene glycol, triethylene glycol, propylene glycol, dipropyleneglycol, neopentyl glycol, glycerol, pentaerythritol, erythritol,sorbitol, mannitol, and the like. Ethylenically unsaturated polyhydricalcohols such as 2-butene-1,4-diol may be used alone or in admixturewith the saturated polyhydric alcohols. Of course, mixtures of saturatedpolyhydric alcohols or mixtures of unsaturated polyhydric alcohols maybe employed.

Suitable polythiols include, without limitation, pentaerythritoltetrakis mecaptopropionate and trimethylolpropane tris thioglycolate.Also, polymeric polythiols can be used. Examples are hydroxyl functionaloligomer or polymer such as polyester polyols and hydroxyl-functionalacrylic copolymers reacted with mercaptopropionic acid or thiol glycolicacid. When present, the polythiol compound is often comprises 2 to 30,such as 5 to 25 percent by weight, based on total weight of theradiation polymerizable materials.

The radiation-curable composition typically contains a photoinitiatorthat consists of any photoinitiators that are capable of generating freeradicals when exposed to UV radiation. A preferred class ofphotoinitiator is bis acyl phosphine oxides, for example Irgacure 819available from Ciba. In certain embodiments, the radiation-curablecomposition contains 1-3% by weight of photoinitiator based on weight ofresin solids of the radiation-curable composition.

In certain embodiments, the coating compositions of the presentinvention are formulated as a one-component composition where a curingagent is admixed with other composition components to form a storagestable composition. In other embodiments, compositions of the presentinvention can be formulated as a two-component composition where acuring agent is added to a pre-formed admixture of the other compositioncomponents just prior to application.

In certain embodiments, the film-forming resin is present in the coatingcompositions of the present invention in an amount greater than 30weight percent, such as 40 to 90 weight percent, or, in some cases, 50to 90 weight percent, with weight percent being based on the totalweight of the coating composition. When a curing agent is used, it may,in certain embodiments, be present in an amount of up to 70 weightpercent, such as 10 to 70 weight percent; this weight percent is alsobased on the total weight of the coating composition.

In certain embodiments, the coating compositions of the presentinvention are in the form of liquid coating compositions, examples ofwhich include aqueous and solvent-based coating compositions andelectrodepositable coating compositions. The coating compositions of thepresent invention may also be in the form of a co-reactable solid inparticulate form, i.e., a powder coating composition. Regardless of theform, the coating compositions of the present invention may be pigmentedor clear, and may be used alone or in combination as primers, basecoats,or topcoats. Certain embodiments of the present invention, as discussionin more detail below, are directed to corrosion resistant primer and/orpretreatment coating compositions. As indicated, certain embodiments ofthe present invention are directed to metal substrate primer coatingcompositions, such as “etch primers,” and/or metal substratepretreatment coating compositions. As used herein, the term “primercoating composition” refers to coating compositions from which anundercoating may be deposited onto a substrate in order to prepare thesurface for application of a protective or decorative coating system. Asused herein, the term “etch primer” refers to primer coatingcompositions that include an adhesion promoting component, such as afree acid as described in more detail below. As used herein, the term“pretreatment coating composition” refers to coating compositions thatcan be applied at very low film thickness to a bare substrate to improvecorrosion resistance or to increase adhesion of subsequently appliedcoating layers. Metal substrates that may be coated with suchcompositions include, for example, substrates comprising steel(including electrogalvanized steel, cold rolled steel, hot-dippedgalvanized steel, among others), aluminum, aluminum alloys,zinc-aluminum alloys, and aluminum plated steel. Substrates that may becoated with such compositions also may comprise more than one metal ormetal alloy, in that the substrate may be a combination of two or moremetal substrates assembled together, such as hot-dipped galvanized steelassembled with aluminum substrates.

The metal substrate primer coating compositions and/or metal substratepretreatment coating compositions of the present invention may beapplied to bare metal. By “bare” is meant a virgin material that has notbeen treated with any pretreatment compositions, such as, for example,conventional phosphating baths, heavy metal rinses, etc. Additionally,bare metal substrates being coated with the primer coating compositionsand/or pretreatment coating compositions of the present invention may bea cut edge of a substrate that is otherwise treated and/or coated overthe rest of its surface.

Before applying a primer coating composition of the present inventionand/or a metal pretreatment composition of the present invention, themetal substrate to be coated may first be cleaned to remove grease,dirt, or other extraneous matter. Conventional cleaning procedures andmaterials may be employed. These materials could include, for example,mild or strong alkaline cleaners, such as those that are commerciallyavailable. Examples include BASE Phase Non-Phos or BASE Phase #6, bothof which are available from PPG Industries, Pretreatment and SpecialtyProducts. The application of such cleaners may be followed and/orpreceded by a water rinse.

The metal surface may then be rinsed with an aqueous acidic solutionafter cleaning with the alkaline cleaner and before contact with a metalsubstrate primer coating composition and/or metal substrate pretreatmentcomposition of the present invention. Examples of suitable rinsesolutions include mild or strong acidic cleaners, such as the dilutenitric acid solutions commercially available.

As previously indicated, certain embodiments of the present inventionare directed to coating compositions comprising an adhesion promotingcomponent. As used herein, the term “adhesion promoting component”refers to any material that is included in the composition to enhancethe adhesion of the coating composition to a metal substrate.

In certain embodiments of the present invention, such an adhesionpromoting component comprises a free acid. As used herein, the term“free acid” is meant to encompass organic and/or inorganic acids thatare included as a separate component of the compositions of the presentinvention as opposed to any acids that may be used to form a polymerthat may be present in the composition. In certain embodiments, the freeacid included within the coating compositions of the present inventionis selected from tannic acid, gallic acid, phosphoric acid, phosphorousacid, citric acid, malonic acid, a derivative thereof, or a mixturethereof. Suitable derivatives include esters, amides, and/or metalcomplexes of such acids.

In certain embodiments, the free acid comprises an organic acid, such astannic acid, i.e., tannin. Tannins are extracted from various plants andtrees which can be classified according to their chemical properties as(a) hydrolyzable tannins, (b) condensed tannins, and (c) mixed tanninscontaining both hydrolyzable and condensed tannins. Tannins useful inthe present invention include those that contain a tannin extract fromnaturally occurring plants and trees, and are normally referred to asvegetable tannins. Suitable vegetable tannins include the crude,ordinary or hot-water-soluble condensed vegetable tannins, such asQuebracho, mimosa, mangrove, spruce, hemlock, gabien, wattles, catechu,uranday, tea, larch, myrobalan, chestnut wood, divi-divi, valonia,summac, chinchona, oak, etc. These vegetable tannins are not purechemical compounds with known structures, but rather contain numerouscomponents including phenolic moieties such as catechol, pyrogallol,etc., condensed into a complicated polymeric structure.

In certain embodiments, the free acid comprises a phosphoric acid, suchas a 100 percent orthophosphoric acid, superphosphoric acid or theaqueous solutions thereof, such as a 70 to 90 percent phosphoric acidsolution.

In addition to or in lieu of such free acids, other suitable adhesionpromoting components are metal phosphates, organophosphates, andorganophosphonates. Suitable organophosphates and organophosphonatesinclude those disclosed in U.S. Pat. No. 6,440,580 at col. 3, line 24 tocol. 6, line 22, U.S. Pat. No. 5,294,265 at col. 1, line 53 to col. 2,line 55, and U.S. Pat. No. 5,306,526 at col. 2, line 15 to col. 3, line8, the cited portions of which being incorporated herein by reference.Suitable metal phosphates include, for example, zinc phosphate, ironphosphate, manganese phosphate, calcium phosphate, magnesium phosphate,cobalt phosphate, zinc-iron phosphate, zinc-manganese phosphate,zinc-calcium phosphate, including the materials described in U.S. Pat.Nos. 4,941,930, 5,238,506, and 5,653,790.

In certain embodiments, the adhesion promoting component comprises aphosphatized epoxy resin. Such resins may comprise the reaction productof one or more epoxy-functional materials and one or morephosphorus-containing materials. Non-limiting examples of suchmaterials, which are suitable for use in the present invention, aredisclosed in U.S. Pat. No. 6,159,549 at col. 3, lines 19 to 62, thecited portion of which being incorporated by reference herein.

In certain embodiments, the adhesion promoting component is present inthe metal substrate primer coating compositions and/or the metalpretreatment coating composition in an amount ranging from 0.05 to 20percent by weight, such as 3 to 15 percent by weight, with the percentsby weight being based on the total weight of the composition.

As previously indicated, in certain embodiments, such as embodimentswhere the coating compositions of the present invention comprise a metalsubstrate primer coating composition and/or a metal pretreatmentcomposition, the composition may also comprise a film-forming resin. Incertain embodiments, the film-forming resin is present in suchcompositions in an amount ranging from 20 to 90 percent by weight, suchas 30 to 80 percent by weight, with the percents by weight being basedon the total weight of the composition.

In certain embodiments, the coating compositions of the presentinvention may also comprise additional optional ingredients, such asthose ingredients well known in the art of formulating surface coatings.Such optional ingredients may comprise, for example, pigments, dyes,surface active agents, flow control agents, thixotropic agents, fillers,anti-gassing agents, organic co-solvents, catalysts, antioxidants, lightstabilizers, UV absorbers and other customary auxiliaries. Any suchadditives known in the art can be used, absent compatibility problems.Non-limiting examples of these materials and suitable amounts includethose described in U.S. Pat. Nos. 4,220,679; 4,403,003; 4,147,769; and5,071,904.

In certain embodiments, the coating compositions of the presentinvention also comprise, in addition to any of the previously describedcorrosion resisting particles, conventional non-chrome corrosionresisting particles. Suitable conventional non-chrome corrosionresisting particles include, but are not limited to, iron phosphate,zinc phosphate, calcium ion-exchanged silica, colloidal silica,synthetic amorphous silica, and molybdates, such as calcium molybdate,zinc molybdate, barium molybdate, strontium molybdate, and mixturesthereof. Suitable calcium ion-exchanged silica is commercially availablefrom W. R. Grace & Co. as SHIELDEX® AC3 and/or SHIELDEX® C303. Suitableamorphous silica is available from W. R. Grace & Co. under the tradenameSYLOID®. Suitable zinc hydroxyl phosphate is commercially available fromElementis Specialties, Inc. under the tradename NALZIN® 2.

These conventional non-chrome corrosion resisting pigments typicallycomprise particles having a particle size of approximately one micron orlarger. In certain embodiments, these particles are present in thecoating compositions of the present invention in an amount ranging from5 to 40 percent by weight, such as 10 to 25 percent by weight, with thepercents by weight being based on the total solids weight of thecomposition.

In certain embodiments, the present invention is directed to coatingcompositions comprising an adhesion promoting component, a phenolicresin and/or an alkoxysilane, in addition to any of the previouslydescribed corrosion resisting particles. Suitable phenolic resinsinclude those resins prepared by the condensation of a phenol or analkyl substituted phenol with an aldehyde. Exemplary phenolic resinsinclude those described in U.S. Pat. No. 6,774,168 at col. 2, lines 2 to22, the cited portion of which being incorporated herein by reference.Suitable alkoxysilanes are described in U.S. Pat. No. 6,774,168 at col.2, lines 23 to 65, incorporated herein by reference, and include, forexample, acryloxyalkoxysilanes, such as γ-acryloxypropyltrimethoxysilaneand methacrylatoalkoxysilane, such asγ-methacryloxypropyltrimethoxysilane, as well as epoxy-functionalsilanes, such as γ-glycidoxypropyltrimethoxysilane. Such compositionsmay also include a solvent, rheological agent, and/or pigment, asdescribed in U.S. Pat. No. 6,774,168 at col. 3, lines 28 to 41, thecited portion of which being incorporated by reference herein.

It has been discovered that the corrosion resisting particles disclosedherein are particularly suitable for use in etch-primers, such asautomotive refinish etch-primers and metal coil coating primers. As aresult, certain embodiments of the present invention are directed toetch-primers comprising: (a) a film-forming resin, such as a polyvinylresin; (b) an adhesion promoting component, such as a free acid; and (c)corrosion resisting particles of the type described herein. As usedherein, the term “refinish” refers to the act of redoing, restoring orrepairing the surface or finish of an article.

The coating compositions of the present invention may be prepared by anyof a variety of methods. For example, in certain embodiments, thepreviously described corrosion resisting particles are added at any timeduring the formulation of a coating composition comprising afilm-forming resin, so long as they form a stable suspension in afilm-forming resin. Coating compositions of the present invention can beprepared by first blending a film-forming resin, the previouslydescribed corrosion resisting particles, and a diluent, such as anorganic solvent and/or water, in a closed container that containsceramic grind media. The blend is subjected to high shear stressconditions, such as by shaking the blend on a high speed shaker, until ahomogeneous dispersion of particles remains suspended in thefilm-forming resin with no visible particle settle in the container. Ifdesired, any mode of applying stress to the blend can be utilized, solong as sufficient stress is applied to achieve a stable dispersion ofthe particles in the film-forming resin.

The coating compositions of the present invention may be applied to asubstrate by known application techniques, such as dipping or immersion,spraying, intermittent spraying, dipping followed by spraying, sprayingfollowed by dipping, brushing, or by roll-coating. Usual spraytechniques and equipment for air spraying and electrostatic spraying,either manual or automatic methods, can be used. While the coatingcompositions of the present invention can be applied to varioussubstrates, such as wood, glass, cloth, plastic, foam, includingelastomeric substrates and the like, in many cases, the substratecomprises a metal.

In certain embodiments of the coating compositions of the presentinvention, after application of the composition to the substrate, a filmis formed on the surface of the substrate by driving solvent, i.e.,organic solvent and/or water, out of the film by heating or by anair-drying period. Suitable drying conditions will depend on theparticular composition and/or application, but in some instances adrying time of from about 1 to 5 minutes at a temperature of about 80 to250° F. (20 to 121° C.) will be sufficient. More than one coating layermay be applied if desired. Usually between coats, the previously appliedcoat is flashed; that is, exposed to ambient conditions for 5 to 30minutes. In certain embodiments, the thickness of the coating is from0.05 to 5 mils (1.3 to 127 microns), such as 0.05 to 3.0 mils (1.3 to76.2 microns). The coating composition may then be heated. In the curingoperation, solvents are driven off and crosslinkable components of thecomposition, if any, are crosslinked. The heating and curing operationis sometimes carried out at a temperature in the range of from 160 to350° F. (71 to 177° C.) but, if needed, lower or higher temperatures maybe used.

As indicated, certain embodiments of the coating compositions of thepresent invention are directed to primer compositions, such as “etchprimers,” while other embodiments of the present invention are directedto metal substrate pretreatment compositions. In either case, suchcompositions are often topcoated with a protective and decorativecoating system, such as a monocoat topcoat or a combination of apigmented base coating composition and a clearcoat composition, i.e., acolor-plus-clear system. As a result, the present invention is alsodirected to multi-component composite coatings comprising at least onecoating layer deposited from a coating composition of the presentinvention. In certain embodiments, the multi-component composite coatingcompositions of the present invention comprise a base-coat film-formingcomposition serving as a basecoat (often a pigmented color coat) and afilm-forming composition applied over the basecoat serving as a topcoat(often a transparent or clear coat).

In these embodiments of the present invention, the coating compositionfrom which the basecoat and/or topcoat is deposited may comprise, forexample, any of the conventional basecoat or topcoat coatingcompositions known to those skilled in the art of, for example,formulating automotive OEM coating compositions, automotive refinishcoating compositions, industrial coating compositions, architecturalcoating compositions, coil coating compositions, and aerospace coatingcompositions, among others. Such compositions typically include afilm-forming resin that may include, for example, an acrylic polymer, apolyester, and/or a polyurethane. Exemplary film-forming resins aredisclosed in U.S. Pat. No. 4,220,679, at col. 2 line 24 to col. 4, line40; as well as U.S. Pat. Nos. 4,403,003, 4,147,679 and 5,071,904.

The present invention is also directed to substrates, such as metalsubstrates, at least partially coated with a coating composition of thepresent invention as well as substrates, such as metal substrates, atleast partially coated with a multi-component composite coating of thepresent invention.

In many cases, the coating compositions of the present invention, whendeposited onto at least a portion of one metal substrate selected fromcold rolled steel, electrogalvanized steel and aluminum and cured,produce a substrate that exhibits corrosion resistance propertiesgreater than the corrosion resistance properties the same substrateexhibits when at least partially coated under the same conditions with asimilar coating composition that does not include the previouslydescribed corrosion resisting particles. In some cases, the coatingcompositions of the present invention, when deposited onto at least aportion of two metal substrates selected from cold rolled steel,electrogalvanized steel and aluminum and cured, produce a substrate thatexhibits corrosion resistance properties greater than the corrosionresistance properties the same two substrates exhibit when at leastpartially coated under the same conditions with a similar coatingcomposition that does not include the previously described corrosionresisting particles. In some cases, the coating compositions of thepresent invention, when deposited onto at least a portion of a coldrolled steel, electrogalvanized steel and aluminum substrate and cured,produce a substrate that exhibits corrosion resistance propertiesgreater than the corrosion resistance properties the same threesubstrates exhibit when at least partially coated under the sameconditions with a similar coating composition that does not include thepreviously described corrosion resisting particles.

As a result, certain embodiments of the present invention are directedto coating compositions that comprise corrosion resisting particlesselected from: (i) magnesium oxide particles having an average primaryparticle size of no more than 100 nanometers; (ii) particles comprisingan inorganic oxide network comprising one or more inorganic oxide;and/or (iii) chemically modified particles having an average primaryparticle size of no more than 500 nanometers, and wherein the corrosionresisting particles are present in the composition in an amountsufficient to result in a composition that, when deposited onto at leasta portion of one metal substrate selected from cold rolled steel,electrogalvanized steel and aluminum and cured, produces a substratethat exhibits corrosion resistance properties greater than the corrosionresistance properties the same substrate exhibits when at leastpartially coated under the same conditions with a similar coatingcomposition that does not include the corrosion resisting particles.

In certain embodiments, the corrosion resisting particles are present inthe composition in an amount sufficient to result in a composition that,when deposited onto at least a portion of two metal substrates selectedfrom cold rolled steel, electrogalvanized steel and aluminum and cured,produces a substrate that exhibits corrosion resistance propertiesgreater than the corrosion resistance properties the same two substratesexhibit when at least partially coated under the same conditions with asimilar coating composition that does not include the corrosionresisting particles. In yet other embodiments, such particles arepresent in the composition in an amount sufficient to result in acomposition that, when deposited onto at least a portion of a coldrolled steel, electrogalvanized steel and aluminum substrate and cured,produces a substrate that exhibits corrosion resistance propertiesgreater than the corrosion resistance properties the same threesubstrates exhibit when at least partially coated under the sameconditions with a similar coating composition that does not include thecorrosion resisting particles.

As used herein, the term “corrosion resistance properties” refers to themeasurement of corrosion prevention on a metal substrate utilizing thetest described in ASTM B 117 (Salt Spray Test). In this test, the coatedsubstrate is scribed with a knife to expose the bare metal substrate.The scribed substrate is placed into a test chamber where an aqueoussalt solution is continuously misted onto the substrate. The chamber ismaintained at a constant temperature. The coated substrate is exposed tothe salt spray environment for a specified period of time, such as 500or 1000 hours. After exposure, the coated substrate is removed from thetest chamber and evaluated for corrosion along the scribe. Corrosion ismeasured by “scribe creep”, which is defined as the total distance thecorrosion has traveled across the scribe measured in millimeters.

In this application, when it is stated that a substrate “exhibitscorrosion resistance properties greater than” another substrate, itmeans that the substrate exhibits less scribe creep (the corrosiontravels across the scribe fewer millimeters) compared to the othersubstrate. In certain embodiments, the corrosion resisting particles arepresent in the coating compositions of the present invention in anamount sufficient to result in a substrate exhibiting corrosionresistance properties at least 15% greater or, in some cases, at least50% greater, than the corrosion resistance properties exhibited by thesame substrate when at least partially coated under the same conditionswith a similar coating composition that does not include the corrosionresisting particles.

As used herein, the term “the same conditions” means that a coatingcomposition is (i) deposited on the substrate at the same or similarfilm thickness as the composition to which it is being compared, and(ii) cured under the same or similar cure conditions, such as curetemperature, humidity, and time, as the composition to which it is beingcompared. As used herein, the term “similar coating composition thatdoes not include the corrosion resisting particles” means that a coatingcomposition contains the same components in the same or similar amountsas the composition to which it is being compared, except that thecorrosion resisting particles described herein, which are included inthe coating compositions of the present invention, are not present andare replaced with conventional non-chrome corrosion resisting particles,such as NALZIN® 2 or SHIELDEX® AC3 (identified earlier).

In many cases, the coating compositions of the present invention, whendeposited onto at least a portion of a metal substrate selected fromcold rolled steel, electrogalvanized steel and aluminum and cured,produce a substrate that exhibits corrosion resistance propertiessimilar to, or, in some cases, greater than, the corrosion resistanceproperties the same substrate exhibits when at least partially coatedunder the same conditions with a conventional chrome-containingcorrosion-resistant composition. In some cases, the coating compositionsof the present invention, when deposited onto at least a portion of twometal substrates selected from cold rolled steel, electrogalvanizedsteel and aluminum and cured, produce a substrate that exhibitscorrosion resistance properties similar to, or, in some cases, greaterthan, the corrosion resistance properties the same two substratesexhibit when at least partially coated under the same conditions with aconventional chrome-containing corrosion-resistant composition. In somecases, the coating compositions of the present invention, when depositedonto at least a portion of a cold rolled steel, electrogalvanized steeland aluminum substrate and cured, produce a substrate that exhibitscorrosion resistance properties similar to, or, in some cases, greaterthan, the corrosion resistance properties the same three substratesexhibit when at least partially coated under the same conditions with aconventional chrome-containing corrosion-resistant composition.

As a result, certain embodiments of the present invention are directedto coating compositions that comprise corrosion resisting particlesselected from: (i) magnesium oxide particles having an average particlesize of no more than 100 nanometers; (ii) particles comprising aninorganic oxide network comprising one or more inorganic oxide; and/or(iii) chemically modified particles having an average particle size ofno more than 500 nanometers, and wherein the corrosion resistingparticles are present in the composition in an amount sufficient toresult in a composition that, when deposited onto at least a portion ofone metal substrate selected from cold rolled steel, electrogalvanizedsteel and aluminum and cured, produces a substrate that exhibitscorrosion resistance properties similar to or, in some embodiments,greater than, the corrosion resistance properties the same substrateexhibits when at least partially coated under the same conditions with aconventional chrome-containing corrosion-resistant composition. Incertain embodiments, such corrosion resisting particles are present inthe composition in an amount sufficient to result in a composition that,when deposited onto at least a portion of two metal substrates selectedfrom cold rolled steel, electrogalvanized steel and aluminum and cured,produces a substrate that exhibits corrosion resistance propertiessimilar to or, in some embodiments, greater than the corrosionresistance properties the same two substrates exhibit when at leastpartially coated under the same conditions with a conventionalchrome-containing corrosion-resistant composition. In yet otherembodiments, such corrosion resisting particles are present in thecomposition in an amount sufficient to result in a composition that,when deposited onto at least a portion of a cold rolled steel,electrogalvanized steel and aluminum substrate and cured, produces asubstrate that exhibits corrosion resistance properties similar to, or,in some embodiments, greater than the corrosion resistance propertiesthe same three substrates exhibit when at least partially coated underthe same conditions with a conventional chrome-containingcorrosion-resistant composition.

In this application, when it is stated that a substrate “exhibitscorrosion resistance properties similar to” another substrate, it meansthat the substrate exhibits scribe creep as measured by ASTM B 117 asdescribed above no more than 10% greater than the substrate to which itis being compared. As used herein, the term “conventionalchrome-containing corrosion-resistant composition” refers to coatingcompositions commercially available from PPG Industries, Inc.,Pittsburgh, Pa., under the tradenames D8099 and DX1791.

As will be appreciated by those skilled in the art based on theforegoing description, certain embodiments of the present invention aredirected to methods for enhancing the corrosion resistance of a metalsubstrate, such methods comprising coating at least a portion of thesubstrate with a primer and/or pretreatment coating composition thatcomprises (a) an adhesion promoting component, and (b) corrosionresisting particles selected from: (i) magnesium oxide particles havingan average particle size of no more than 100 nanometers; (ii) particlescomprising an inorganic oxide network comprising one or more inorganicoxide; and/or (iii) chemically modified particles having an averageparticle size of no more than 500 nanometers. In certain embodiments,such primer compositions are substantially free of chromium containingmaterial and/or also comprise a film-forming resin, such as a polyvinylpolymer.

As will also be appreciated by the skilled artisan, certain embodimentsof the present invention are directed to methods for enhancing thecorrosion resistance of a metal substrate. The methods comprise coatingat least a portion of the substrate with a primer and/or pretreatmentcoating composition that comprises (a) an adhesion promoting component,and (b) corrosion resisting particles selected from: (i) magnesium oxideparticles having an average primary particle size of no more than 100nanometers; (ii) particles comprising an inorganic oxide networkcomprising one or more inorganic oxide; and/or (iii) chemically modifiedparticles having an average primary particle size of no more than 500nanometers.

Illustrating the invention are the following examples, which, however,are not to be considered as limiting the invention to their details.Unless otherwise indicated, all parts and percentages in the followingexamples, as well as throughout the specification, are by weight.

EXAMPLES

The following Particle Examples describe the preparation of corrosionresisting particles suitable for use in certain embodiments of thecoating compositions of the present invention.

Particle Example 1

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (see table 1) were added and stirredfor 15 minutes. Then, Charge C (see Table 1) was added over 5 minutesand stirred for 30 minutes. Then, 300 grams of water was added andheated to 40° C. The reaction mixture was stirred at 40° C. for sixhours and then cooled to ambient temperature. The solid precipitated wasfiltered off, washed with acetone and dried at ambient temperature for24 hours.

Particle Example 2

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 1) were added and stirredfor 15 minutes. Then, Charge C (See Table 1) was added over 5 minutesand stirred for 6 minutes. Then, 300 grams of water was added and heatedto 40° C. The reaction mixture was stirred at 40° C. for 375 minutes andthen cooled to ambient temperature. The solid precipitated was filteredoff, washed with acetone and dried at ambient temperature for 24 hours.

Particle Example 3

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 1) were added and stirredfor three minutes. Then, (See Table 1) was added over 5 minutes andstirred for 32 minutes. Then, 200 grams of water was added and heated to40° C. The reaction mixture was stirred at 40° C. for six hours and thencooled to ambient temperature. Then, five grams of triethylamine in 30grams of water was added and stirred for an hour. The solid precipitatedwas filtered off, washed with acetone and dried at ambient temperaturefor 24 hours.

Particle Example 4

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 1) were added and stirredfor 45 minutes. Then, Charge C (See Table 1) was added over 5 minutesand stirred for 30 minutes. Then, 200 grams of water was added andheated to 40° C. The reaction mixture was stirred at 40° C. for twohours. Then, charge D, sparged with nitrogen stream continuously, (SeeTable 1) was added over thirty minutes and stirred at 40° C. for twohours. Reaction mixture was cooled to ambient temperature and nine gramsof triethylamine were added, and stirred for 90 minutes. The solidprecipitated was filtered off, washed with acetone and dried at ambienttemperature for 24 hours.

Particle Example 5

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 1) were added and stirredfor 85 minutes. The temperature was raised to 75° C. and stirred at 75°C. for 55 minutes. Then, the reaction mixture was cooled to 50° C. andCharge C (See Table 1) was added over 5 minutes and stirred for 25minutes. Then, charge D, sparged with nitrogen stream continuouslyduring addition, (See Table 1) was added over thirty minutes and stirredat 50° C. for 375 minutes. The reaction mixture was cooled to ambienttemperature and the solid precipitated was filtered off, washed withacetone and dried at ambient temperature for 24 hours.

TABLE 1 Particle Particle Particle Particle Particle Example 1 Example 2Example 3 Example 4 Example 5 Charge A (grams) Deionized water 200.0200.0 200.0 200.0 800 Charge B (grams) Cerium(III) acetate 1.5H₂0¹ 34.00.0 0.0 0.0 102.0 Yttrium acetate Hydrate² 0.0 26.3 0.0 0.0 0.0Manganese acetate 4H₂O³ 0.0 0.0 24.2 0.0 0.0 Zirconium sulfate⁴ 0.0 0.00.0 27.9 0.0 Zinc acetate dihydrate⁵ 22.0 22.0 22.0 22.0 66.0 Charge C(grams) Silquest TEOS pure silane⁶ 48.0 48.0 48.0 48.0 144.0 Acetone200.0 200.0 200.0 200.0 600.0 Charge D (grams) Triethylamine⁷ 5.0 30.0Deionized water 50.0 180.0 ¹Available from Prochem Inc. ²Available fromAldrich. ³Available from Aldrich. ⁴Available from ICN Biomedicals Inc.⁵Available from Barker Industries. ⁶Available from GE silicones.⁷Available from Aldrich.

Particle Example 6

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 2) were added, heated to 50°C. and stirred for ten minutes. Then, Charge C (See Table 2) was addedover 5 minutes and stirred for 40 minutes. Then Charge D, sparged withnitrogen stream continuously during addition, (See Table 2) was addedover thirty minutes and stirred at 50° C. for six hours. The reactionmixture was cooled to ambient temperature and the solid precipitated wasfiltered off, washed with water and acetone sequentially and dried atambient temperature for 24 hours.

Particle Example 7

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 2) were added and stirred at50° C. for 30 minutes. Then, the temperature was raised to 75° C. andstirred for an hour. Then, the reaction mixture was cooled to 50° C. andCharge C (See Table 2) was added over 5 minutes and stirred for 25minutes. Then charge D (See Table 2) was added over thirty minutes andstirred at 50° C. for 320 minutes. The reaction mixture was then cooledto ambient temperature and the solid precipitated was filtered off,washed with water and acetone sequentially, and dried at ambienttemperature for 24 hours.

Particle Example 8

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 2) were added and thetemperature was raised to 75° C. and stirred for an hour. Then, thereaction mixture was cooled to 50° C., and Charge C (See Table 2) wasadded over 5 minutes and stirred for 35 minutes. Then, charge D, spargedwith nitrogen stream continuously during addition, (See Table 2) wasadded over thirty minutes and stirred at 50° C. for six hours. Thereaction mixture was cooled to ambient temperature and the solidprecipitated was filtered off, washed with acetone and dried at ambienttemperature for 24 hours.

Particle Example 9

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A (See Table 1) was added and stirred at 50° C. Then,Charge B and Charge C (See Table 2) were added over two hourssimultaneously. Then, the reaction mixture was stirred at 50° C. forthree hours. The solid precipitated was filtered off, washed with waterand acetone sequentially, and dried at ambient temperature for 48 hours.The solid obtained was ground using mortar and pestle.

Particle Example 10

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A (See Table 2) was added and stirred at 50° C. ChargeB and Charge C (See Table 2) were added over two hours simultaneously.Then, the reaction mixture was stirred at 50° C. for three hours. Thesolid precipitated was filtered off, washed with water and acetonesequentially, and dried at ambient temperature for 48 hours. The solidobtained was ground using mortar and pestle.

TABLE 2 Particle Particle Particle Particle Particle Example 6 Example 7Example 8 Example 9 Example 10 Charge A (grams) Deionized water 676.0400.0 3200.0 300.0 300.0 Charge B Cerium(III) acetate 1.5H₂0¹ 51.0 51.0408.0 51.0 51.0 Zinc acetate dihydrate² 33.0 33.0 264.0 33.0 33.0Sulfuric acid ~36N³ 0.0 0.0 0.0 0.0 5.9 Deionized water 0.0 0.0 0.0740.0 740.0 Charge C (grams) Silquest TEOS pure silane⁴ 144.0 72.0 576.00.0 0.0 Acetone 300.0 300.0 2400.0 0.0 0.0 Sodium Silicate solution⁵94.0 94.0 Charge D (grams) Triethylamine⁶ 15.0 0.0 120.0 Ammoniumhydroxide⁷ 0.0 16.6 0.0 Deionized water 90.0 90.0 720.0 ¹Available fromProchem Inc. ²Available from Barker Industries. ³Available from FischerScientific. ⁴Available from GE silicones. ⁵30% solids aqueous solution;Available from PPG Industries. ⁶Available from Fisher Scientific.⁷Available from Mallinckrodt.

Particle Example 11

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 3) were added and stirredfor 30 minutes. Then, the temperature was raised to 50° C. and stirredfor 105 minutes. Then, 100 grams of water was added and the reactionmixture was heated to 60° C. and stirred for 45 minutes. Then, the heatsource was removed. At a reaction temperature of 34° C., charge C (SeeTable 3) was added over five minutes. The reaction mixture was stirredfor 30 minutes at 30° C. Charge D, sparged with nitrogen streamcontinuously during addition, (See Table 3) was added over thirtyminutes and stirred at 30° C. for 260 minutes. The reaction mixture wascooled to ambient temperature and the solid precipitated was filteredoff, washed with acetone and dried at ambient conditions for 24 hours.

Particle Example 12

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 3) were added and stirredfor 20 minutes. Then, 100 grams of water was added and the reactionmixture was heated to 60° C. and stirred for an hour. Then, the heatsource was removed. At a reaction temperature of 48° C., charge C (SeeTable 3) was added over two minutes. The reaction mixture was stirredfor three hours while cooling to 26° C. The solid precipitated wasfiltered off, washed with acetone and dried at ambient temperature for24 hours.

Particle Example 13

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 3) were added, heated to 40°C. and stirred for 45 minutes. Then, the temperature was raised to 50°C. and stirred for 105 minutes. The heat source was removed and at areaction temperature of 38° C., charge C (See Table 3) was added overtwo minutes. The reaction mixture was stirred for two hours whilecooling to 26° C. The solid precipitated was filtered off, washed withacetone and dried at ambient temperature.

Particle Example 14

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (See Table 3) were added and stirredfor 15 minutes. Then, the temperature was raised to 50° C. Charge C (SeeTable 3) was added over five minutes and stirred for 30 minutes. ChargeD, sparged with nitrogen stream continuously during addition, (See Table3) was added over thirty minutes and stirred at 50° C. for four hours.The reaction mixture was cooled to ambient temperature and the solidprecipitated was filtered off, washed with water and acetonesequentially and dried at ambient temperature for 24 hours.

TABLE 3 Particle Particle Particle Particle Example 11 Example 12Example 13 Example 14 Charge A (grams) Deionized water 200.0 200.0 200.0300.0 Charge B (grams) Cerium (III) acetate 1.5H₂0¹ 34.0 34.0 34.0 0.0Zinc acetate dihydrate² 22.0 22.0 22.0 33.0 Magnesium(II)acetate•4H₂O³21.2 21.2 0.0 31.8 Charge C (grams) Silquest TEOS pure silane⁴ 48.0 0.00.0 72.0 Acetone 200.0 0.0 0.0 300.0 Phosphoric acid 85%⁵ 0.0 40.3 0.00.0 Sodium metasilicate⁶ 0.0 0.0 48.0 0.0 Deionized water 0.0 50.0 100.00.0 Charge D (grams) Triethylamine⁷ 10.0 15.0 Deionized water 60.0 90.0¹Available from Prochem Inc. ²Available from Barker Industries.³Available from Acros Organics. ⁴Available from GE silicones. ⁵Availablefrom Fisher Scientific. ⁶Available from Aldrich. ⁷Available from FisherScientific.

Particle Example 15

To a reaction flask, charge A and Charge B (see Table 3a) were added andstirred for 15 minutes. Then, Charge C (see Table 3a) was added overfive minutes and stirred for 150 minutes. Then, 20 grams of deionizedwater was added and stirred for 40 minutes. The precipitated solid wasfiltered off, washed with water and acetone sequentially and air driedfor 24 hours.

Particle Example 16

A reaction flask was equipped with a stirrer, thermocouple and acondenser. Charge A and charge B (see Table 3a) were added, heated to50° C. and stirred for an hour. Then, charge C (see Table 3a) was addedover 5 minutes and stirred for 30 minutes. Then, charge D, sparged withnitrogen stream continuously during addition, ((see Table 3a) was addedover thirty minutes and stirred for three hours. The solid precipitatedwas filtered off, washed with acetone and dried at ambient temperaturefor 24 hours.

TABLE 3a Particle Particle Example 15 Example 16 Charge A (grams)Deionized water 50.0 800 Charge B (grams) Cerium (III) acetate 1.5H₂0¹8.8 51.0 Zinc acetate dihydrate² 4.8 99.0 Charge C (grams) Silquest TEOSpure silane³ 0.0 144.0 Acetone 0.0 600.0 Laponite RD⁴ 20.0 Charge D(grams) Triethylamine⁵ 30.0 Deionized water 180.0 ¹Available fromProchem Inc. ²Available from Barker Industries. ³Available from GEsilicones. ⁴Synthetic clay available from Southern Clay Products, Inc.⁵Available from Fisher Scientific.

Particle Example 17

A suitable reaction vessel equipped for vacuum distillation was flushedwith nitrogen gas. To the flask was added 1600 grams of Snowtex O (a 20%solution of colloidal silica in water available from Nissan Chemical). Amixture of 6.5 grams of trimethoxysilylpropyl methacrylate in 154 gramsof water with the pH adjusted to 5.0 with acetic acid was added to theflask over 5 minutes at ambient temperature. The mixture was stirred for45 minutes at ambient temperature. Then 64 grams of vinyltrimethoxysilane was added to the reaction mixture over 5 minutes. Thereaction mixture was again stirred for 45 minutes at ambienttemperature. A total of 1280 grams of butyl Cellosolve was then added tothe reaction mixture over about 20 minutes at ambient temperature. Themixture was again stirred for 45 minutes at ambient temperature. Themixture was slowly heated to 90° C. and vacuum distilled. A total of1679 grams of distillate was removed. The final mixture was a slightlyhazy, low viscosity mixture about 29% solids as measured at 110° C. for60 minutes.

Coating Composition Examples 1A to 1E

Coating compositions were prepared using the components and weights (ingrams) shown in Table 4. All materials in the A pack of the formulation,were added under agitation with a Cowles blade in the order listed up toethanol. 17.42 grams of ethanol was held out from the total until laterin the preparation. Next, the poly(vinyl butyral) resin was slowly addedwhile still under agitation and left to mix for 15 minutes. Epoxy resinwas then added. Next, corrosion resisting particles, if any, andpigment(s) were added with heavy mixing for about ten minutes. Then, therest of the ethanol and other solvents were slowly added. This finalmixture was allowed to mix for ten minutes and was then added to asealed 8 ounce glass container containing approximately 150 grams of theabove material to approximately 125 grams of zircoa beads. This sealedcontainer was then left on a paint shaker for two to 4 hours. Afterremoving the paste from the paint shaker, the milling beads werefiltered out with a standard paint filter and the finished material wasready.

The B pack of the formulation was prepared by adding the components to asuitable vessel under agitation with a paddle blade and allowing to mixfor 20 minutes. When ready to spray, the two compositions were mixed.

TABLE 4 Example Example Example Example Example Pack Material 1A 1B 1C1D 1E A DOWANOL PM¹ 9.18 9.18 9.18 9.18 9.18 A BLS-2700² 10.17 10.1710.17 10.17 10.17 A Ethanol³ 56.51 56.51 56.51 56.51 56.51 A ButvarB-90⁴ 6.9 6.9 6.9 6.9 6.9 A EPON 834-X-80⁵ 3 3 3 3 3 A Particle Example5 — 2.26 — — — A Particle Example 9 — — 2.26 — — A Particle Example 10 —— — 2.26 — A Particle Example 7 — — — — 2.26 A K-White G105⁶ 2.26 2.262.26 2.26 2.26 A Aerosil 200⁷ 0.6 0.6 0.6 0.6 0.6 A Toluene⁸ 6.91 6.916.91 6.91 6.91 A Xylene⁹ 5.19 5.19 5.19 5.19 5.19 A Isobutyl Alcohol¹⁰5.89 5.89 5.89 5.89 5.89 B Ethanol³ 85.28 85.28 85.28 85.28 85.28 BButanol¹¹ 9.43 9.43 9.43 9.43 9.43 B Phosphoric Acid 85%¹² 1.59 1.591.59 1.59 1.59 B Deionized Water 0.09 0.09 0.09 0.09 0.09 ¹Propyleneglycol monomethyl ether commercially available from BASF Corp. ²Phenolicresin commercially available from Georgia Pacific. ³Organic solventcommercially available from ChemCentral Corp. ⁴Poly (vinyl butyral)resin commercially available from Solutia Inc.⁵Epichlorohydrin-Bisphenol A resin commercially available fromResolution Performance Products. ⁶Aluminum triphosphate compoundcommercially available from Tayca. ⁷Silicon dioxide commerciallyavailable from Cabot Corp. ⁸Commercially available from Ashland ChemicalCo. ⁹Commercially available from Ashland Chemical Co. ¹⁰Commerciallyavailable from Avecia. ¹¹Commercially available from BASF Corp.¹²Commercially available from Akzo Chemicals Inc.

Test Substrates

The compositions of Table 4, as well as Examples 1F and 1G (describedbelow), were applied to the test substrates identified in Table 5. Thesubstrates were prepared by first cleaning with a wax and greaserremover (DX330, commercially available from PPG Industries, Inc.) andallowed to dry. The panels were then sanded with 180 grit using a DAorbital sander and again cleaned with DX330. The compositions wereapplied using a DeVilbiss GTI HVLP spray gun with a 1.4 spray tip, N2000Cap, and 30 psi at gun. Each composition was applied in two coats with afive-minute flash in between to film builds of 0.50 to approximately1.25 mils (12.7 to 31.8 microns). A minimum of twenty to thirty minutesand no more than one hour of time was allowed to elapse before applyinga PPG Industries, Inc. global sealer D 839 over each composition. Thesealer was mixed and applied as a wet-on-wet sealer to approximately 1.0to 2.0 mils (25.4 to 50.8 microns) of paint and allowed to flashforty-five minutes before applying base coat. Deltron DBC base coat,commercially available from PPG Industries, Inc., was applied over thesealer in two coats with five to ten minutes flash time between coats toa film build thickness of approximately 0.5 mils (12.7 microns). Thebase coat was allowed approximately fifteen minutes time to flash beforeapplying D893 Global clear coat, commercially available from PPGIndustries, Inc., in two coats with five to ten minutes to flash betweencoats to a film build of 2.50 to 3.00 mils (63.5 to 76.2 microns).Sealer, base coat, and clear coat were mixed as the procedure for theseproducts recommended by PPG Industries, Inc. Salt spray resistance wastested as described in ASTM B 117. Panels removed from salt spraytesting after 1000 hours were measured for scribe creep across thescribe. Scribe creep values were reported as an average of six (6)measurements. Results are illustrated in Table 5, with lower valueindicated better corrosion resistance results.

TABLE 5 Substrate Ex. 1A Ex. 1B Ex. 1C Ex. 1D Ex. 1E Ex. 1F¹³ Ex. 1G¹⁴Cold Rolled 4.3 11.1 9.5 3.9 8.3 22 0 Steel (APR10288) G-60 7.2 3.3 1.10 0 4.3 0 Galvanized (APR18661) Aluminum 10.5 Delaminated DelaminatedDelaminated Delaminated 1 0 (APR21047) ¹³D-831 commercially availablefrom PPG Industries, Inc., Pittsburgh, PA. ¹⁴D8099 FastDrying-Anti-Corrosion Etch Primer commercially available from PPGIndustries, Inc., Pittsburgh, PA.

Coating Composition Examples 2A to 2F

Coating compositions were prepared using the components and weights (ingrams) shown in Table 6. Coatings were prepared in the same manner asdescribed for Coating Composition Examples 1A to 1E.

TABLE 6 Example Example Example Example Example Example Pack Material 2A2B 2C 2D 2E 2F A DOWANOL PM¹ 9.18 9.18 9.18 9.18 9.18 9.18 A BLS-2700²10.17 10.17 10.17 10.17 10.17 10.17 A Ethanol³ 56.51 56.51 56.51 56.5156.51 56.51 A Butvar B-90⁴ 6.9 6.9 6.9 6.9 6.9 6.9 A EPON 834-X-80⁵ 3 33 3 3 3 A Particle Example 5 — 2.26 — — — — A Particle Example 10 — — —— — 2.26 A Particle Example 8 — — 2.26 — — — A Particle Example 15 — — —2.26 — — A Particle Example 6 — — — — 2.26 — A K-White G105⁶ 2.26 2.262.26 2.26 2.26 2.26 A Aerosil 200⁷ 0.6 0.6 0.6 0.6 0.6 0.6 A Toluene⁸6.91 6.91 6.91 6.91 6.91 6.91 A Xylene⁹ 5.19 5.19 5.19 5.19 5.19 5.19 AIsobutyl Alcohol¹⁰ 5.89 5.89 5.89 5.89 5.89 5.89 B Ethanol³ 85.28 85.2885.28 85.28 85.28 85.28 B Butanol¹¹ 9.43 9.43 9.43 9.43 9.43 9.43 BPhosphoric Acid 1.59 1.59 1.59 1.59 1.59 1.59 85%¹² B Deionized Water0.09 0.09 0.09 0.09 0.09 0.09

Test Substrates

The compositions of Table 6, as well as Examples 2F and 2G (describedbelow), were applied to the test substrates identified in Table 7 usingthe same procedure as was described above for Coating CompositionExamples 1A to 1G. Results are illustrated in Table 7, with lower valueindicated better corrosion resistance results.

TABLE 7 Example Example Example Example Example Example Ex. Ex.Substrate 2A 2B 2C 2D 2E 2F 2G¹³ 2H¹⁴ Cold Rolled 4.2 11.3 2.3 10 7.713.7 23 10.3 Steel (APR10288) G-60 5.3 2 1.2 0.9 0 0.5 1.3 0 Galvanized(APR18661) Aluminum Delaminated Delaminated Delaminated DelaminatedDelaminated Delaminated 0.5 0 (APR21047)

Coating Composition Examples 3A to 3D

Coating compositions were prepared using the components and weights (ingrams) shown in Table 8. Coatings were prepared in the same manner asdescribed for Coating Composition Examples 1A to 1E.

TABLE 8 Pack Material Example 3A Example 3B Example 3C Example 3D ADOWANOL PM¹ 8.82 9.18 9.18 9.18 A BLS-2700² 9.77 10.17 10.17 10.17 AEthanol³ 54.28 56.51 56.51 56.51 A Butvar B-90⁴ 6.63 6.9 6.9 6.9 A EPON834-X-80⁵ 2.88 — — — A Particle Example 5 2.17 — — — A Particle Example12 — 2.17 — — A Particle Example 13 — — — 2.17 A Particle Example 14 — —2.17 — A Aerosil 200⁷ 0.58 0.58 0.58 0.58 A Toluene⁸ 6.64 6.64 6.64 6.64A Xylene⁹ 4.99 4.99 4.99 4.99 A Isobutyl Alcohol¹⁰ 5.66 5.66 5.66 5.66 BEthanol³ 81.92 81.92 81.92 81.92 B Butanol¹¹ 9.06 9.06 9.06 9.06 BPhosphoric Acid 85%¹² 1.53 1.53 1.53 1.53 B Deionized Water 0.09 0.090.09 0.09

Test Substrates

The compositions of Table 8, as well as Examples 3E and 3F (describedbelow), were applied to the test substrates identified in Table 9 usingthe same procedure as was described above for Coating CompositionExamples 1A to 1G. Results are illustrated in Table 9, with lower valueindicated better corrosion resistance results.

TABLE 9 Example Example Example Example Example Example Substrate 3A 3B3C 3D 3E¹⁵ 3F¹⁴ Cold Rolled Delaminated 12.7 9 14.5 Delaminated 2.7Steel (APR10288) G-60 14.3 7.2 7 9.3 11.8 2.2 Galvanized (APR18661)Aluminum 6.2 9.2 4.7 4.5 4.7 0.5 (APR21047) ¹⁵DPX-171 commerciallyavailable from PPG Industries, Inc., Pittsburgh, PA.

Coating Composition Example 4A

Coating composition 4A was prepared using the components and weights (ingrams) shown in Table 10. The coating was prepared in the same manner asdescribed for Coating Composition Examples 1A to 1E.

TABLE 10 Pack Material Example 4A A DOWANOL PM¹ 9.18 A BLS-2700² 10.17 AEthanol³ 56.51 A Butvar B-90⁴ 6.9 A EPON 834-X-80⁵ 3 A Particle Example11 2.26 A Aerosil 200⁷ 0.6 A Toluene⁸ 6.91 A Xylene⁹ 5.19 A IsobutylAlcohol¹⁰ 5.89 B Ethanol³ 85.28 B Butanol¹¹ 9.43 B Phosphoric Acid 85%¹²1.59 B Deionized Water 0.09

Test Substrates

The composition of Table 10, as well as Examples 4B and 4C (describedbelow), were applied to the test substrates identified in Table 11 usingthe same procedure as was described above for Coating CompositionExamples 1A to 1G. Results are illustrated in Table 11, with lower valueindicated better corrosion resistance results.

TABLE 11 Substrate Example 4A Example 4B¹⁵ Example 4C¹⁴ Cold RolledSteel 2.1 24.2 0 (APR10288) G-60 Galvanized 7.3 2 0 (APR18661) AluminumDelaminated 0.7 0 (APR21047)

Coating Composition Examples 5a to 5G

Coating compositions were prepared using the components and weights (ingrams) shown in Table 12. Coatings were prepared in the same manner asdescribed for Coating Composition Examples 1A to 1E.

TABLE 12 Pack Material Ex. 5A Ex. 5B Ex. 5C Ex. 5D Ex. 5E Ex. 5F Ex. 5GA DOWANOL PM¹ 9.18 9.18 9.18 9.18 9.18 9.18 9.18 A BLS-2700² 10.17 10.1710.17 10.17 10.17 10.17 10.17 A Ethanol³ 56.51 56.51 56.51 56.51 56.5156.51 56.51 A Butvar B-90⁴ 6.9 6.9 6.9 6.9 6.9 6.9 6.9 A Zinc chromate¹⁶2.26 — — — — — — A Magnesium Oxide¹⁷ — 2.26 — — — — — A Particle Example1 — — 2.26 — — — — A Particle Example 2 — — — 2.26 — — — A ParticleExample 3 — — — — 2.26 — — A Particle Example 4 — — — — — 2.26 — ANalzin-2¹⁸ — — — — — — 2.26 A Aerosil 200⁷ 0.6 0.6 0.6 0.6 0.6 0.6 0.6 AToluene⁸ 6.91 6.91 6.91 6.91 6.91 6.91 6.91 A Xylene⁹ 5.18 5.18 5.185.18 5.18 5.18 5.18 A Isobutyl Alcohol¹⁰ 5.89 5.89 5.89 5.89 5.89 5.895.89 B Ethanol³ 85.28 85.28 85.28 85.28 85.28 85.28 85.28 B Butanol¹¹9.43 9.43 9.43 9.43 9.43 9.43 9.43 B Phosphoric Acid 1.59 1.59 1.59 1.591.59 1.59 1.59 85%¹² B Deionized Water 0.09 0.09 0.09 0.09 0.09 0.090.09 ¹⁶Zinc tetroxy chromate commercially available from PMG Colours.¹⁷Magnesium oxide, average primary particle size of 20 nanometers,commercially available from Nanostructured & Amorphous Materials, Inc.¹⁸Zinc hydroxyl phosphate anti-corrosion pigment commercially availablefrom Elementis Specialties, Inc.

Test Substrates

The compositions of Table 12, as well as Examples 5H and 5I (describedbelow), were applied to the test substrates identified in Table 13 usingthe same procedure as was described above for Coating CompositionExamples 1A to 1G. Results are illustrated in Table 13, with lower valueindicated better corrosion resistance results.

TABLE 13 Ex. Ex. Ex. Substrate Ex. 5A 5B Ex. 5C Ex. 5D Ex. 5E Ex. 5F Ex.5G 5H¹⁵ 5I¹⁴ Cold Rolled 6.2 4 0.7 1.3 3.3 0 13 10.7 8.2 Steel(APR10288) G-60 10.7 5.2 15.2 13.2 11.8 14.3 15.6 10 7.8 Galvanized(APR18661) Aluminum Delam. 1 Delam. Delam. Delam. Delam. Delam. 6.2 0(APR21047)

Coating Composition Examples 6a to 6H

Coating compositions were prepared using the components and weights (ingrams) shown in Table 14. Coatings were prepared in the same manner asdescribed for Coating Composition Examples 1A to 1E.

TABLE 14 Pack Material Ex. 6A Ex. 6B Ex. 6C Ex. 6D Ex. 6E Ex. 6F Ex. 6GEx. 6H A DOWANOL PM¹ 9.18 9.18 9.18 9.18 9.18 9.18 9.18 9.18 A BLS-2700²10.17 10.17 10.17 10.17 10.17 10.17 10.17 10.17 A Ethanol³ 56.51 56.5156.51 56.51 56.51 56.51 56.51 56.51 A Butvar B-90⁴ 6.9 6.9 6.9 6.9 6.96.9 6.9 6.9 A EPON 834-X-80⁵ 3 — — — 3 — 3 3 A Magnesium Oxide¹⁷ — 2.26— — — 2.26 2.26 2.26 A Particle Example 1 — — 2.26 — 2.26 2.26 — 2.26 AParticle Example 11 2.26 2.26 — 2.26 — — 2.26 — A K-White G105⁶ — — —2.26 2.26 2.26 2.26 — A Aerosil 200⁷ 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 AToluene⁸ 6.91 6.91 6.91 6.91 6.91 6.91 6.91 6.91 A Xylene⁹ 5.18 5.185.18 5.18 5.18 5.18 5.18 5.18 A Isobutyl Alcohol¹⁰ 5.89 5.89 5.89 5.895.89 5.89 5.89 5.89 B Ethanol³ 85.28 85.28 85.28 85.28 85.28 85.28 85.2885.28 B Butanol¹¹ 9.43 9.43 9.43 9.43 9.43 9.43 9.43 9.43 B PhosphoricAcid 1.59 1.59 1.59 1.59 1.59 1.59 1.59 1.59 85%¹² B Deionized Water0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09

Test Substrates

The compositions of Table 14, as well as Examples 6I and 6J (describedbelow), were applied to the test substrates identified in Table 15 usingthe same procedure as was described above for Coating CompositionExamples 1A to 1G. Results are illustrated in Table 15, with lower valueindicated better corrosion resistance results.

TABLE 15 Substrate Ex. 6A Ex. 6B Ex. 6C Ex. 6D Ex. 6E Ex. 6F Ex. 6G Ex.6H Ex. 6I¹⁵ Ex. 6J¹⁴ Cold Rolled 2.1 2.5 0 0 0 0 0.5 13.7 24.2 0 Steel(APR10288) G-60 7.3 3.2 4.4 2.6 2.7 0.5 0.7 0.5 2 0 Galvanized(APR18661) Aluminum Delam. 0 Delam. Delam. 0.5 0 0 0 0.7 0 (APR21047)

Coating Composition Example 7A

Coating composition 7A was prepared using the components and weights (ingrams) shown in Table 16. The coating was prepared in the same manner asdescribed for Coating Composition Examples 1A to 1E.

TABLE 16 Pack Material Example 7A A DOWANOL PM¹ 3.1 A BLS-2700² 9.86 AEthanol³ 54.75 A Butvar B-90⁴ 6.68 A EPON 834-X-80⁵ 3.44 A ParticleExample 17 20.82 A 2-mercaptobenzothiazole 1.01 A Aerosil 200⁷ 0.58 AToluene⁸ 6.69 A Xylene⁹ 5.03 A Isobutyl Alcohol¹⁰ 5.71 B Ethanol³ 82.63B Butanol¹¹ 9.14 B Phosphoric Acid 85%¹² 2.6 B Deionized Water 0.09

Test Substrates

The composition of Table 16, as well as Examples 7B and 7C (describedbelow), were applied to the test substrates identified in Table 17 usingthe same procedure as was described above for Coating CompositionExamples 1A to 1G. Results are illustrated in Table 17, with lower valueindicated better corrosion resistance results.

TABLE 17 Example Example Example Substrate 7A 7B¹⁵ 7C¹⁴ Cold RolledSteel 0.5 17.4 0.3 (APR10288) G-60 Galvanized 0.1 4.4 0 (APR18661)Aluminum (APR21047) 0.4 Delaminated 0

Coating Compositions Examples 8A to 8B

Coating compositions 8A and 8B were prepared using the components andweights (in grams) shown in Table 18. The coatings were prepared in thesame manner as described for Coating Composition Examples 1A to 1E.

TABLE 18 Example Pack Material Example 8A 8B A DOWANOL PM¹ 10.55 3.68 ABLS-2700² 11.7 11.7 A Ethanol³ 65.35 64.97 A Butvar B-90⁴ 7.93 7.93 AZinc Tetroxy Chromate 2.6 — A Particle Example 17 — 9.52 A Aerosil 200⁷0.69 0.69 A Toluene⁸ 7.95 7.94 A Xylene⁹ 5.97 5.97 A Isobutyl Alcohol¹⁰6.77 6.77 B Ethanol³ 98.07 98.05 B Butanol¹¹ 10.85 10.85 B PhosphoricAcid 85%¹² 1.83 1.83 B Deionized Water 0.11 0.11

Test Substrates

The compositions of Table 18, as well as Examples 8C and 8D (describedbelow), were applied to the test substrates identified in Table 19 usingthe same procedure as was described above for Coating CompositionExamples 1A to 1G. Results are illustrated in Table 19, with lower valueindicated better corrosion resistance results.

TABLE 19 Example Example Substrate 8A Example 8B Example 8C¹⁵ 8D¹³ ColdRolled Steel 8.3 2.3 25.3 24.1 (APR10288) G-60 Galvanized 12.8 3.5 8.28.9 (APR18661) Aluminum 1.4 Delaminated 8.9 3.7 (APR21047)

Coating Compositions Examples 9A to 9B

Coating compositions 9A and 9B were prepared using the components andweights (in grams) shown in Table 20. The coatings were prepared in thesame manner as described for Coating Composition Examples 1A to 1E.

TABLE 20 Example Pack Material Example 9A 9B A DOWANOL PM¹ 3.17 3.13 ABLS-2700² 9.86 9.86 A Ethanol³ 56.05 55.34 A Butvar B-90⁴ 6.68 6.68 AEPON 834-X-80⁵ 3.44 3.44 A VANSIL ® W-50¹⁶ 20 20 A Particle Example 17 —9.55 A 2-mercaptobenzothiazole 1.01 1.01 A NANOBYK-3650 8.59 — A Aerosil200⁷ 0.6 0.6 A Toluene⁸ 6.85 6.76 A Xylene⁹ 5.15 5.08 A IsobutylAlcohol¹⁰ 5.85 5.77 B Ethanol³ 82.63 82.63 B Butanol¹¹ 9.14 9.14 BPhosphoric Acid 85%¹² 2.6 2.6 B Deionized Water 0.09 0.09 ¹⁶Wollastonite(calcium metasilicate) commercially available from R. T. Vanderbilt Co.,Inc.

Test Substrates

The compositions of Table 20, as well as Examples 9C and 9D (describedbelow), were applied to the test substrates identified in Table 21 usingthe same procedure as was described above for Coating CompositionExamples 1A to 1G. Results are illustrated in Table 21, with lower valueindicated better corrosion resistance results.

TABLE 21 Example Example Example Example Substrate 9A 9B 9C¹³ 9D¹³ ColdRolled Steel 5.6 2.1 15.2 5 (APR10288) G-60 Galvanized 1.7 1.8 6.3 0(APR18661) Aluminum (APR21047) 0 0 5.2 0

Coating Compositions Examples 10A to 10C

Coating compositions 10A to 10C were prepared using the components andweights (in grams) shown in Table 22. The coatings were prepared in thesame manner as described for Coating Composition Examples 1A to 1E.

TABLE 22 Example Example Example Pack Material 10A 10B 10C A DOWANOL PM¹9.18 3.1 3.1 A BLS-2700² 10.17 9.86 9.86 A Ethanol³ 56.51 54.75 54.75 AButvar B-90⁴ 6.9 6.68 6.68 A EPON 834-X-80⁵ 3 3.44 3.44 A Talc¹⁷ — 20 20A Particle Example 17 — 10.41 — A 2-mercaptobenzothiazole — 1.01 1.01 ANANOBYK-3650 — — 8.9 A Aerosil 200⁷ 0.6 0.58 0.58 A Toluene⁸ 6.91 6.696.69 A Xylene⁹ 5.19 5.03 5.03 A Isobutyl Alcohol¹⁰ 5.89 5.71 5.71 BEthanol³ 85.28 85.28 85.28 B Butanol¹¹ 9.43 9.43 9.43 B Phosphoric Acid85%¹² 1.59 1.59 1.59 B Deionized Water 0.09 0.09 0.09 ¹⁷Available fromBarretts Minerals.

Test Substrates

The compositions of Table 22, as well as Examples 10D and 10E (describedbelow), were applied to the test substrates identified in Table 23 usingthe same procedure as was described above for Coating CompositionExamples 1A to 1G. Results are illustrated in Table 23, with lower valueindicated better corrosion resistance results.

TABLE 23 Example Example Example Example Example Substrate 10A 10B 10C10D¹³ 10E¹³ Cold Rolled Delami- 4.8 1 23 1.8 Steel nated (APR10288) G-6019.5 9.3 5 9.2 0.5 Galvanized (APR18661) Aluminum 23.5 8.2 0 1.5 0(APR21047)

Coating Composition Example 11

Coating composition 11 was prepared using the components and weights (ingrams) shown in Table 24.

TABLE 24 Example Pack Component Material 11 A 1 Ancamine ® 2569¹ 30.21 A2 Ancamine ® 2432² 20.01 A 3 Ancamine ® K54³ 1.84 A 4 Butanol 55.27 A 5Xylene 9.53 A 6 TI-PURE ® R-900 Titanium dioxide⁴ 19.05 A 7 Carbon Black0.10 A 8 Magnesium oxide⁵ 44.88 A 9 Butanol 27.49 B 10 EPON ™ 8111⁶111.0 B 11 EPON ™ 828⁷ 681.0 B 12 Xylene 180.0 B 13 Silquest ® A-187⁸20.0 B 14 Bentone ® SD-2⁹ 71.0 B 15 Oxsol ® 100¹⁰ 11.0 ¹Polyamide resincommercially available from Pacific Anchor. ²Polyamine resincommercially available from Pacific Anchor.³2,4,6-Tri(dimethylaminomethyl) phenol commercially available fromPacific Anchor. ⁴Commercially available from DuPont. ⁵Magnesium oxide,average primary particle size of 20 nanometers, commercially availablefrom Nanostructured & Amorphous Materials, Inc. ⁶Epoxy resincommercially available from Hexion Specialty Chemicals. ⁷Epoxy resincommercially available from Hexion Specialty Chemicals.⁸Gamma-Glycidoxypropyltrimethoxy Silane commercially available fromCrompton Corporation. ⁹Rheology additive commercially available fromElementis Specialties, Inc. ¹⁰Parachlorobenzotrifluoride commerciallyavailable from Occidental Chemical Co.

Pack A was prepared by mixing components 1-8 under high shearconditions. 120 grams of 2 mm zircoa beads were added as a grindingmedium. The mixture was then sealed in an 8 ounce jar and agitated on ahigh speed paint shaker for three hours. A viscous dispersion was thenachieved with a hegman rating of 5.5 units. Component 9 was then addedfor viscosity reduction and to facilitate filtering of the zircoa beads.The resulting dispersion was then filtered to remove the zircoa beads.Pack B was prepared separately from Pack A by mixing components 10-15under high shear conditions. When ready to spray, 75 milliliters of PackA was mixed with 75 milliliters of Pack B.

Test Substrates

The composition of Table 24 was applied to aluminum substrates that wereeither pretreated with Alodine® 1200S (a chromate conversion coatingcommercially available from Henkel Technologies) or clad with purealuminum (Alclad commercially available from Alcoa Inc.). The panelswere lightly sanded to improve adhesion. Application was via aconventional HVLP spray gun. The coatings were allowed to cure atambient conditions for 2 hours prior to applying a commerciallyavailable urethane topcoat (CA8200/8211 available from PPG Industries,Inc.). The primed and topcoated panels were allowed to completely curefor one week at ambient conditions and then tested for salt sprayresistance as described in ASTM B 117. The panels were evaluated inregular intervals and examined for corrosion at the scribe, blistering,blushing, and other surface defects. A duplicate set of panels wereprepared with a zinc chromate containing primer. Results are illustratedin Table 25.

TABLE 25 Scribe Blisters Scribe Blisters Scribe Blisters Appearance (288Appearance (504 Appearance (1500 Primer Substrate (288 hours) hours)(504 hours) hours) (1500 hours) hours) Example Alclad Black and NoneBlack and None Black, white None 11 white white some shiny corrosioncorrosion Example Alodine Black None Black None Black and None 11corrosion corrosion white corrosion ZnCrO₄ Alclad Black None Black NoneBlack and None Control corrosion corrosion white corrosion ZnCrO₄Alodine None None Black None Black and None Control corrosion whitecorrosion

Coating Composition Example 12

A urethane acrylate was prepared by equipping a 5-liter reactor vesselwith a stirring blade, nitrogen inlet, and one feed inlet. Charge 1 (seebelow) was added to the vessel.

Charge 1 Component Weight (g) Desmodur Z 4470¹ BA 1730.7 IONOL² 3.12Dibutyl tin dilaurate 1.52 Triphenyl phosphite 7.1 ¹Desmodur Z 4470 isthe isocyanurate of isophorone diisocyanate commercially available fromBayer. ²IONOL is 2,6-Di-t-Butyl Cresol.

Charge 1 was heated in the reactor to a temperature of 69° C. under anitrogen blanket. Upon reaching 69° C., Charge B was added over a periodof 45 minutes or at a rate to maintain the reaction temperature at nogreater than 75° C.

Charge B Component Weight (g) Sartomer SR-9003³ 393.1 Hydroxy ethylacrylate 391.1 ³Sartomer SR-9003 is a propoxylated neopentyl glycoldiacrylate monomer and is commercially available from Sartomer Company,Inc., Exton, PA.

Upon completion of the addition of Charge B, the reaction temperaturewas maintained at 80′C for one hour. After the one-hour hold, Charge Cwas added.

Charge C Component Weight (g) 1,6-Hexanediol 99

With the addition of Charge C, the reaction was held until the NCO peakwas no longer visible in an IR spectra of the reaction material. Aftercompletion of the reaction, Charge D was added.

Charge D Component Weight (g) Sartomer SR-9003 339.5 Tert-butyl acetate340.1

The urethane acrylate had a resin solids content of 73.99% (measured at1 hour/110° C.).

A coating composition was prepared by mixing 47.68 g of the previouslydescribed urethane acrylate resin, 3.90 g of an acrylate-functionaldiluent (commercially available as SR 9003 from Sartomer), 2.04 g of awetting and dispersing agent (commercially available as Disperbyk-110from Byk Chemie), 21.43 g of magnesium oxide particles (average primaryparticle size of 20 nanometers, commercially available fromNanostructured & Amorphous Materials, Inc.), and 22.28 g of tert-butylacetate. The mixture was mechanically shaken for 2-3 hours with 100 g ofzircoa beads, and then filtered through a cone filter to give apigmented paste. To the paste was added: 3.90 g of anacrylate-functional adhesion promoter (commercially available as CD 9053from Sartomer), 2.02 g of a photoinitiator (commercially available asIrgacure 819 from Ciba Chemicals) and 3.84 g of a tri-functional thiol(Trimethylolpropane tris(3-mercaptopropionate commercially availablefrom Sigma-Aldrich). This formula contained a 5.32:1 acrylate:thiolratio.

The composition was sprayed, using an HVLP cup gun, onto bare Aluminum2024 T3 panels. Bare Al panels were prepared by wet sanding with 400grit paper, washing with water, followed by wiping with acetone. Thesprayed formula was allowed to flash for 5 minutes, followed by a 5minute cure with an H&S Autoshot 400 UV-A lamp at 10 inches from thesubstrate. The coating demonstrated a tack-free surface after the 5minutes of UV-A exposure. The dry film thickness (DFT) of the primer wasapproximately 1 mil.

The cured coating was then topcoated with CA 8214/F36173, which is aflat gray 2-component polyurethane topcoat (commercially available fromPRC-DeSoto), and allowed to cure for 10 days at ambient conditions (˜77F and ˜50% relative humidity). The dry film thickness (DFT) of thetopcoat was approximately 2 mils. The topcoated sample showed excellentinter-coat adhesion (between primer and topcoat), while also showinggood adhesion to the bare aluminum substrate.

The panel were scribed and placed into an ASTM B-117 salt spray cabinetfor 500 hours. After the allotted time period, the panel showed onlysmall blisters and a minute amount of dark corrosion.

It will be readily appreciated by those skilled in the art thatmodifications may be made to the invention without departing from theconcepts disclosed in the foregoing description. Such modifications areto be considered as included within the following claims unless theclaims, by their language, expressly state otherwise. Accordingly, theparticular embodiments described in detail herein are illustrative onlyand are not limiting to the scope of the invention which is to be giventhe full breadth of the appended claims and any and all equivalentsthereof.

We claim:
 1. A method of coating a substrate comprising: applying afirst coating composition to at least a portion of the substrate,wherein the coating composition comprises: epoxy functional material,organic solvent, and magnesium oxide particles; and wherein thesubstrate comprises a 2000 series aluminum alloy.
 2. The method of claim1, wherein the coating composition further comprises an amine functionalmaterial.
 3. The method of claim 1, further comprising applying anadditional coating onto the at least partially coated substrate.
 4. Themethod of claim 3, wherein the additional coating comprisespolyurethane.
 5. The method of claim 1, wherein the first coatingcomposition has a dry film thickness of 0.5 to 1.25 mils.
 6. The methodof claim 1, wherein the magnesium oxide particles have a surface area ofat least 10 m²/g.
 7. The method of claim 6, wherein the magnesium oxideparticles are platy.
 8. The method of claim 6, wherein the magnesiumoxide particles are spherical.
 9. The method of claim 6, wherein themagnesium oxide particles are cubical.
 10. The method of claim 6,wherein the magnesium oxide particles are acicular.
 11. The method ofclaim 1, wherein the first coating composition is substantiallychromate-free.
 12. The method of claim 3, wherein both the first andsecond coating compositions are substantially chromate-free.
 13. Themethod of claim 1, wherein the 2000 series aluminum alloy comprises analuminum cladding.
 14. The method of claim 1, comprisingsurface-treating the substrate prior to application of the first coatingcomposition.
 15. A coated substrate comprising: (a) a 2000 seriesaluminum alloy; (b) a first cured thermoset coating that is depositedfrom a composition comprising an epoxy functional material and magnesiumoxide particles.
 16. The coated substrate of claim 15, wherein thecomposition further comprises an amine functional material.
 17. Thecoated substrate of claim 15, further comprising: (d) a second coatingon at least a portion of the first coating.
 18. The coated substrate ofclaim 15, wherein the second coating comprises polyurethane.
 19. Thecoated substrate of claim 15, wherein the first coating composition hasa dry film thickness of 0.5 to 1.5 mils.
 20. The coated substrate ofclaim 15, wherein the magnesium oxide particles have a surface area ofat least 10 m²/g.
 21. The coated substrate of claim 20, wherein themagnesium oxide particles are platy.
 22. The coated substrate of claim20, wherein the magnesium oxide particles are spherical.
 23. The coatedsubstrate of claim 20, wherein the magnesium oxide particles arecubical.
 24. The coated substrate of claim 20 wherein the magnesiumoxide particles are acicular.
 25. The coated substrate of claim 15,wherein the first coating composition is substantially chromate-free.26. The coated substrate of claim 17, wherein both the first and secondcoating compositions are substantially chromate-free.
 27. The coatedsubstrate of claim 15, wherein the 2000 series aluminum alloy comprisesan aluminum cladding.
 28. The coated substrate of claim 15, furthercomprising a surface treatment applied to the substrate prior toapplication of the first cured thermoset coating.
 29. The coatedsubstrate of claim 15, wherein the substrate has better corrosionresistance than a substrate coated with a cured thermoset coating havingthe same epoxy functional material but lacking the magnesium oxideparticle as measured by ASTM B 117 after 1000 hours.
 30. The coatedsubstrate of claim 17, further comprising a surface treatment applied tothe substrate prior to application of the first cured thermoset coating,and wherein the surface treatment, first coating and second coating aresubstantially chromate-free.
 31. The coated substrate of claim 17,wherein the second coating is an aerospace coating.
 32. The coatedsubstrate of claim 30, wherein the second coating is an aerospacecoating.
 33. The method of claim 1, wherein the first coatingcomposition is applied by spraying.
 34. A method for enhancing thecorrosion resistance of a substrate comprising 2000 series aluminumalloy, comprising coating at least a portion of the substrate with acomposition comprising: (a) an epoxy functional material; (b) organicsolvent; and (c) magnesium oxide particles.